diff --git a/build_all.sh b/build_all.sh
index aa7072f..522b0de 100755
--- a/build_all.sh
+++ b/build_all.sh
@@ -118,7 +118,7 @@ public class TestRunner {
     public static void main(String[] args) {
         LauncherDiscoveryRequest request = LauncherDiscoveryRequestBuilder.request()
             .selectors(
-                selectPackage("haus.nightmare.lib3270j")
+                selectPackage("haus.nightmare")
             )
             .build();
 
diff --git a/j3270/src/main/java/haus/nightmare/j3270/J3270App.java b/j3270/src/main/java/haus/nightmare/j3270/J3270App.java
index 0543ca9..bb0e177 100644
--- a/j3270/src/main/java/haus/nightmare/j3270/J3270App.java
+++ b/j3270/src/main/java/haus/nightmare/j3270/J3270App.java
@@ -53,6 +53,8 @@ public class J3270App extends JFrame implements ConnectionListener, ScreenUpdate
         buildUI();
         buildMenuBar();
 
+        ThemeManager.addThemeChangeListener(this::onThemeChanged);
+
         pack();
         setLocationRelativeTo(null);
         setMinimumSize(new Dimension(640, 400));
@@ -97,10 +99,16 @@ public class J3270App extends JFrame implements ConnectionListener, ScreenUpdate
         getContentPane().add(statusBar, BorderLayout.SOUTH);
     }
 
+    private void onThemeChanged(UITheme theme) {
+        buildMenuBar();
+        statusBar.applyTheme(theme);
+        ThemeManager.applyThemeToWindow(this);
+        terminalPanel.repaint();
+    }
+
     private void buildMenuBar() {
         JMenuBar menuBar = new JMenuBar();
-        menuBar.setBackground(new Color(30, 30, 30));
-        menuBar.setBorder(BorderFactory.createMatteBorder(0, 0, 1, 0, new Color(50, 50, 50)));
+        ThemeManager.styleMenuBar(menuBar);
 
         int shortcutMask = Toolkit.getDefaultToolkit().getMenuShortcutKeyMaskEx();
 
@@ -145,6 +153,31 @@ public class J3270App extends JFrame implements ConnectionListener, ScreenUpdate
         }));
         viewMenu.addSeparator();
 
+        // UI Theme Submenu
+        JMenu themeMenu = createMenu("UI Theme");
+        ButtonGroup themeGroup = new ButtonGroup();
+
+        JRadioButtonMenuItem darkThemeItem = new JRadioButtonMenuItem("Dark Mode", ThemeManager.isDark());
+        ThemeManager.styleMenuItem(darkThemeItem);
+        darkThemeItem.addActionListener(e -> {
+            haus.nightmare.j3270.config.Settings.setJavaUiTheme(UITheme.DARK);
+            ThemeManager.setTheme(UITheme.DARK);
+        });
+        themeGroup.add(darkThemeItem);
+        themeMenu.add(darkThemeItem);
+
+        JRadioButtonMenuItem lightThemeItem = new JRadioButtonMenuItem("Light Mode", ThemeManager.isLight());
+        ThemeManager.styleMenuItem(lightThemeItem);
+        lightThemeItem.addActionListener(e -> {
+            haus.nightmare.j3270.config.Settings.setJavaUiTheme(UITheme.LIGHT);
+            ThemeManager.setTheme(UITheme.LIGHT);
+        });
+        themeGroup.add(lightThemeItem);
+        themeMenu.add(lightThemeItem);
+
+        viewMenu.add(themeMenu);
+        viewMenu.addSeparator();
+
         // CodePage Submenu
         JMenu cpMenu = createMenu("Code Page");
         String[] codePages = {
@@ -174,8 +207,7 @@ public class J3270App extends JFrame implements ConnectionListener, ScreenUpdate
         for (String cpItem : codePages) {
             String cpId = cpItem.split(" -")[0].trim();
             JMenuItem cpMi = new JMenuItem(cpItem);
-            cpMi.setBackground(new Color(40, 40, 40));
-            cpMi.setForeground(new Color(200, 200, 200));
+            ThemeManager.styleMenuItem(cpMi);
             cpMi.addActionListener(e -> changeCodePage(cpId));
             cpMenu.add(cpMi);
         }
@@ -185,8 +217,7 @@ public class J3270App extends JFrame implements ConnectionListener, ScreenUpdate
         JMenu gfxMenu = createMenu("Graphics Mode");
         for (GraphicsMode gm : GraphicsMode.values()) {
             JMenuItem gmMi = new JMenuItem(gm.name());
-            gmMi.setBackground(new Color(40, 40, 40));
-            gmMi.setForeground(new Color(200, 200, 200));
+            ThemeManager.styleMenuItem(gmMi);
             gmMi.addActionListener(e -> changeGraphicsMode(gm));
             gfxMenu.add(gmMi);
         }
@@ -257,14 +288,12 @@ public class J3270App extends JFrame implements ConnectionListener, ScreenUpdate
 
     private JMenu createMenu(String name) {
         JMenu menu = new JMenu(name);
-        menu.setForeground(new Color(200, 200, 200));
-        return menu;
+        return ThemeManager.styleMenu(menu);
     }
 
     private JMenuItem createMenuItem(String name, int mnemonic, Runnable action, boolean useAlt) {
         JMenuItem item = new JMenuItem(name);
-        item.setBackground(new Color(40, 40, 40));
-        item.setForeground(new Color(200, 200, 200));
+        ThemeManager.styleMenuItem(item);
         if (mnemonic > 0) {
             int modifier = useAlt ? KeyEvent.ALT_DOWN_MASK : Toolkit.getDefaultToolkit().getMenuShortcutKeyMaskEx();
             item.setAccelerator(KeyStroke.getKeyStroke(mnemonic, modifier));
@@ -693,9 +722,9 @@ public class J3270App extends JFrame implements ConnectionListener, ScreenUpdate
         JTextArea area = new JTextArea(text);
         area.setEditable(false);
         area.setFont(new Font(Font.MONOSPACED, Font.PLAIN, 13));
-        area.setBackground(new Color(30, 30, 30));
-        area.setForeground(new Color(200, 200, 200));
+        ThemeManager.styleTextArea(area);
         JScrollPane sp = new JScrollPane(area);
+        ThemeManager.styleScrollPane(sp);
         sp.setPreferredSize(new Dimension(380, 430));
         JOptionPane.showMessageDialog(this, sp, "Key Mappings", JOptionPane.INFORMATION_MESSAGE);
     }
@@ -726,9 +755,9 @@ public class J3270App extends JFrame implements ConnectionListener, ScreenUpdate
         JTextArea area = new JTextArea(text);
         area.setEditable(false);
         area.setFont(new Font(Font.MONOSPACED, Font.PLAIN, 13));
-        area.setBackground(new Color(30, 30, 30));
-        area.setForeground(new Color(200, 200, 200));
+        ThemeManager.styleTextArea(area);
         JScrollPane sp = new JScrollPane(area);
+        ThemeManager.styleScrollPane(sp);
         sp.setPreferredSize(new Dimension(440, 430));
         JOptionPane.showMessageDialog(this, sp, "Mnemonic Keystroke Reference", JOptionPane.INFORMATION_MESSAGE);
     }
@@ -758,45 +787,47 @@ public class J3270App extends JFrame implements ConnectionListener, ScreenUpdate
         Boolean cliTn3270e = null;
         GraphicsMode cliGraphicsMode = null;
         String configFile = null;
+
         java.util.List<String> remainingArgs = new java.util.ArrayList<>();
         for (int i = 0; i < args.length; i++) {
-            if ("--debug".equals(args[i]) || "-d".equals(args[i])) {
+            String arg = args[i];
+            if ("-d".equals(arg) || "--debug".equals(arg)) {
                 debug = true;
-            } else if ("--tls".equals(args[i]) || "--ssl".equals(args[i]) || "-s".equals(args[i])) {
+            } else if ("-s".equals(arg) || "--tls".equals(arg) || "--ssl".equals(arg)) {
                 cliTls = true;
-            } else if ("--no-verify-cert".equals(args[i]) || "--insecure".equals(args[i]) || "-k".equals(args[i])) {
+            } else if ("--no-verify-cert".equals(arg) || "--insecure".equals(arg) || "-k".equals(arg)) {
                 cliNoVerifyCert = true;
-            } else if ("--no-tn3270e".equals(args[i]) || "--plain-tn3270".equals(args[i]) || "--plain".equals(args[i]) || "-P".equals(args[i]) || "-p".equals(args[i]) || "--non-e".equals(args[i])) {
+            } else if ("--no-tn3270e".equals(arg) || "--plain-tn3270".equals(arg) || "--plain".equals(arg) || "-P".equals(arg) || "-p".equals(arg) || "--non-e".equals(arg)) {
                 cliTn3270e = false;
-            } else if ("--tn3270e".equals(args[i])) {
+            } else if ("--tn3270e".equals(arg)) {
                 cliTn3270e = true;
-            } else if (args[i].startsWith("--graphics=")) {
-                cliGraphicsMode = GraphicsMode.fromString(args[i].substring(11));
-            } else if (("--graphics".equals(args[i]) || "-g".equals(args[i])) && i + 1 < args.length && !args[i + 1].startsWith("-")) {
+            } else if (arg.startsWith("--graphics=")) {
+                cliGraphicsMode = GraphicsMode.fromString(arg.substring(11));
+            } else if (("--graphics".equals(arg) || "-g".equals(arg)) && i + 1 < args.length && !args[i + 1].startsWith("-")) {
                 cliGraphicsMode = GraphicsMode.fromString(args[++i]);
-            } else if ("--no-graphics".equals(args[i])) {
+            } else if ("--no-graphics".equals(arg)) {
                 cliGraphicsMode = GraphicsMode.NONE;
-            } else if (("-c".equals(args[i]) || "--config".equals(args[i])) && i + 1 < args.length) {
+            } else if (("-c".equals(arg) || "--config".equals(arg)) && i + 1 < args.length) {
                 configFile = args[++i];
+            } else if (arg.startsWith("-")) {
+                System.err.println("Unknown option: " + arg);
             } else {
-                remainingArgs.add(args[i]);
+                remainingArgs.add(arg);
             }
         }
 
-        Level logLevel = debug ? Level.ALL : Level.INFO;
+        Level logLevel = debug ? Level.FINE : Level.INFO;
+
         Logger globalRoot = Logger.getLogger("");
         for (java.util.logging.Handler h : globalRoot.getHandlers()) {
             globalRoot.removeHandler(h);
         }
-        globalRoot.setLevel(Level.ALL);
 
-        java.util.logging.Filter appFilter = record -> {
-            String name = record.getLoggerName();
-            return name != null && (name.startsWith("haus.nightmare.lib3270j") || name.startsWith("haus.nightmare.j3270"));
-        };
+        java.util.logging.Filter appFilter = record -> record.getLoggerName() != null &&
+                (record.getLoggerName().startsWith("haus.nightmare") || record.getLoggerName().startsWith("org.pubvm"));
 
         ConsoleHandler consoleHandler = new ConsoleHandler();
-        consoleHandler.setLevel(logLevel);
+        consoleHandler.setLevel(Level.ALL);
         consoleHandler.setFormatter(new SimpleFormatter());
         consoleHandler.setFilter(appFilter);
         globalRoot.addHandler(consoleHandler);
@@ -837,6 +868,8 @@ public class J3270App extends JFrame implements ConnectionListener, ScreenUpdate
         } catch (Exception e) {
             log.fine("Could not set system look and feel");
         }
+        ThemeManager.applyUIManagerDefaults(haus.nightmare.j3270.config.Settings.getJavaUiTheme());
+        ThemeManager.setTheme(haus.nightmare.j3270.config.Settings.getJavaUiTheme());
 
         System.setProperty("apple.laf.useScreenMenuBar", "true");
         System.setProperty("apple.awt.application.name", "j3270");
diff --git a/j3270/src/main/java/haus/nightmare/j3270/config/Settings.java b/j3270/src/main/java/haus/nightmare/j3270/config/Settings.java
index 036ba70..e751893 100644
--- a/j3270/src/main/java/haus/nightmare/j3270/config/Settings.java
+++ b/j3270/src/main/java/haus/nightmare/j3270/config/Settings.java
@@ -1,5 +1,6 @@
 package haus.nightmare.j3270.config;
 
+import haus.nightmare.j3270.ui.UITheme;
 import java.util.prefs.Preferences;
 import java.awt.Color;
 import java.io.*;
@@ -17,6 +18,15 @@ public class Settings {
         AUTO_CONNECT
     }
 
+    public static UITheme getJavaUiTheme() {
+        String themeStr = prefs.get("javaUiTheme", UITheme.DARK.name());
+        return UITheme.fromString(themeStr);
+    }
+
+    public static void setJavaUiTheme(UITheme theme) {
+        prefs.put("javaUiTheme", (theme != null ? theme : UITheme.DARK).name());
+    }
+
     public static String getFontFamily() {
         return prefs.get("fontFamily", "Monospaced");
     }
@@ -229,6 +239,11 @@ public class Settings {
                 switch (key) {
                     case "fontFamily": setFontFamily(value); break;
                     case "fontSize": setFontSize(Integer.parseInt(value)); break;
+                    case "javaUiTheme":
+                    case "theme":
+                    case "uiTheme":
+                        setJavaUiTheme(UITheme.fromString(value));
+                        break;
                     default:
                         log.warning("Unknown appearance key: " + key);
                 }
@@ -322,6 +337,7 @@ public class Settings {
 
             // [appearance]
             w.println("[appearance]");
+            w.println("javaUiTheme = " + getJavaUiTheme().name());
             w.println("fontFamily = " + getFontFamily());
             w.println("fontSize = " + getFontSize());
             w.println();
diff --git a/j3270/src/main/java/haus/nightmare/j3270/ft/FileTransferDialog.java b/j3270/src/main/java/haus/nightmare/j3270/ft/FileTransferDialog.java
index 44b7453..f64620e 100644
--- a/j3270/src/main/java/haus/nightmare/j3270/ft/FileTransferDialog.java
+++ b/j3270/src/main/java/haus/nightmare/j3270/ft/FileTransferDialog.java
@@ -1,6 +1,7 @@
 package haus.nightmare.j3270.ft;
 
 import haus.nightmare.j3270.ui.HostDirectoryDialog;
+import haus.nightmare.j3270.ui.ThemeManager;
 import haus.nightmare.lib3270j.ft.FTConfig;
 import haus.nightmare.lib3270j.ft.FTConstants;
 
@@ -88,6 +89,7 @@ public class FileTransferDialog extends JDialog {
         // Local File
         localFileField = new JTextField(20);
         browseLocalButton = new JButton("Browse...");
+        ThemeManager.styleButton(browseLocalButton, ThemeManager.ButtonVariant.DEFAULT);
         browseLocalButton.addActionListener(e -> browseLocalFile());
         JPanel localPanel = new JPanel(new BorderLayout(5, 0));
         localPanel.setOpaque(false);
@@ -98,6 +100,7 @@ public class FileTransferDialog extends JDialog {
         // Host File
         hostFileField = new JTextField(20);
         browseHostButton = new JButton("Browse Host...");
+        ThemeManager.styleButton(browseHostButton, ThemeManager.ButtonVariant.DEFAULT);
         browseHostButton.addActionListener(e -> browseHostDirectory());
         JPanel hostPanel = new JPanel(new BorderLayout(5, 0));
         hostPanel.setOpaque(false);
@@ -154,10 +157,7 @@ public class FileTransferDialog extends JDialog {
         // Host-specific options panel (TSO dataset allocation)
         JPanel hostOptsPanel = new JPanel(new GridLayout(2, 4, 5, 5));
         hostOptsPanel.setOpaque(false);
-        hostOptsPanel.setBorder(BorderFactory.createTitledBorder(
-                BorderFactory.createLineBorder(new Color(60, 60, 60)),
-                "TSO Allocation Options (Send Only)"));
-        ((javax.swing.border.TitledBorder)hostOptsPanel.getBorder()).setTitleColor(new Color(180, 180, 180));
+        hostOptsPanel.setBorder(ThemeManager.createTitledBorder("TSO Allocation Options (Send Only)"));
 
         hostOptsPanel.add(new JLabel("RECFM:"));
         recfmField = new JTextField(5);
@@ -181,10 +181,7 @@ public class FileTransferDialog extends JDialog {
         // CMS options
         JPanel vmOptsPanel = new JPanel(new BorderLayout(5, 0));
         vmOptsPanel.setOpaque(false);
-        vmOptsPanel.setBorder(BorderFactory.createTitledBorder(
-                BorderFactory.createLineBorder(new Color(60, 60, 60)),
-                "CMS Options"));
-        ((javax.swing.border.TitledBorder)vmOptsPanel.getBorder()).setTitleColor(new Color(180, 180, 180));
+        vmOptsPanel.setBorder(ThemeManager.createTitledBorder("CMS Options"));
         
         optionsField = new JTextField(20);
         vmOptsPanel.add(new JLabel("Additional Options: "), BorderLayout.WEST);
@@ -200,9 +197,11 @@ public class FileTransferDialog extends JDialog {
         buttonPanel.setOpaque(false);
         
         transferButton = new JButton("Start Transfer");
+        ThemeManager.styleButton(transferButton, ThemeManager.ButtonVariant.PRIMARY);
         transferButton.addActionListener(e -> startTransfer());
         
         cancelButton = new JButton("Close");
+        ThemeManager.styleButton(cancelButton, ThemeManager.ButtonVariant.CANCEL);
         cancelButton.addActionListener(e -> dispose());
         
         buttonPanel.add(cancelButton);
@@ -212,7 +211,7 @@ public class FileTransferDialog extends JDialog {
 
         setContentPane(mainPanel);
         
-        applyTheme(mainPanel);
+        ThemeManager.applyThemeToWindow(this);
         updateOptionStates();
     }
 
diff --git a/j3270/src/main/java/haus/nightmare/j3270/ui/ConnectDialog.java b/j3270/src/main/java/haus/nightmare/j3270/ui/ConnectDialog.java
index 0e700b9..f3a029c 100644
--- a/j3270/src/main/java/haus/nightmare/j3270/ui/ConnectDialog.java
+++ b/j3270/src/main/java/haus/nightmare/j3270/ui/ConnectDialog.java
@@ -34,24 +34,21 @@ public class ConnectDialog extends JDialog {
     private void buildUI() {
         JPanel mainPanel = new JPanel(new GridBagLayout());
         mainPanel.setBorder(BorderFactory.createEmptyBorder(16, 16, 16, 16));
-        mainPanel.setBackground(new Color(30, 30, 30));
         GridBagConstraints gbc = new GridBagConstraints();
-        gbc.insets = new Insets(4, 4, 4, 4);
+        gbc.insets = new Insets(5, 6, 5, 6);
         gbc.fill = GridBagConstraints.HORIZONTAL;
 
-        Font labelFont = new Font(Font.SANS_SERIF, Font.PLAIN, 14);
-        Color fg = new Color(200, 200, 200);
+        Font labelFont = new Font(Font.SANS_SERIF, Font.PLAIN, 13);
 
         // Host
         gbc.gridx = 0;
         gbc.gridy = 0;
         JLabel hostLabel = new JLabel("Host:");
-        hostLabel.setForeground(fg);
         hostLabel.setFont(labelFont);
         mainPanel.add(hostLabel, gbc);
         gbc.gridx = 1;
         gbc.weightx = 1.0;
-        hostField = createDarkField(20);
+        hostField = createField(20);
         mainPanel.add(hostField, gbc);
 
         // Port
@@ -59,12 +56,11 @@ public class ConnectDialog extends JDialog {
         gbc.gridy = 1;
         gbc.weightx = 0;
         JLabel portLabel = new JLabel("Port:");
-        portLabel.setForeground(fg);
         portLabel.setFont(labelFont);
         mainPanel.add(portLabel, gbc);
         gbc.gridx = 1;
         gbc.weightx = 1.0;
-        portField = createDarkField(6);
+        portField = createField(6);
         portField.setText("23");
         mainPanel.add(portField, gbc);
 
@@ -73,16 +69,14 @@ public class ConnectDialog extends JDialog {
         gbc.gridy = 2;
         gbc.weightx = 0;
         JLabel modelLabel = new JLabel("Model:");
-        modelLabel.setForeground(fg);
         modelLabel.setFont(labelFont);
         mainPanel.add(modelLabel, gbc);
         gbc.gridx = 1;
         gbc.weightx = 1.0;
         modelCombo = new JComboBox<>(TerminalModel.values());
         modelCombo.setSelectedItem(TerminalModel.IBM_3279_4);
-        modelCombo.setBackground(new Color(45, 45, 45));
-        modelCombo.setForeground(fg);
         modelCombo.setFont(new Font(Font.MONOSPACED, Font.PLAIN, 13));
+        ThemeManager.styleComboBox(modelCombo);
         mainPanel.add(modelCombo, gbc);
 
         // LU Name
@@ -90,12 +84,11 @@ public class ConnectDialog extends JDialog {
         gbc.gridy = 3;
         gbc.weightx = 0;
         JLabel luLabel = new JLabel("LU Name:");
-        luLabel.setForeground(fg);
         luLabel.setFont(labelFont);
         mainPanel.add(luLabel, gbc);
         gbc.gridx = 1;
         gbc.weightx = 1.0;
-        luField = createDarkField(12);
+        luField = createField(12);
         mainPanel.add(luField, gbc);
 
         // Graphics Mode
@@ -103,16 +96,14 @@ public class ConnectDialog extends JDialog {
         gbc.gridy = 4;
         gbc.weightx = 0;
         JLabel graphicsLabel = new JLabel("Graphics:");
-        graphicsLabel.setForeground(fg);
         graphicsLabel.setFont(labelFont);
         mainPanel.add(graphicsLabel, gbc);
         gbc.gridx = 1;
         gbc.weightx = 1.0;
         graphicsCombo = new JComboBox<>(haus.nightmare.lib3270j.graphics.GraphicsMode.values());
         graphicsCombo.setSelectedItem(haus.nightmare.j3270.config.Settings.getGraphicsMode());
-        graphicsCombo.setBackground(new Color(45, 45, 45));
-        graphicsCombo.setForeground(fg);
         graphicsCombo.setFont(new Font(Font.SANS_SERIF, Font.PLAIN, 13));
+        ThemeManager.styleComboBox(graphicsCombo);
         mainPanel.add(graphicsCombo, gbc);
 
         // Code Page
@@ -120,7 +111,6 @@ public class ConnectDialog extends JDialog {
         gbc.gridy = 5;
         gbc.weightx = 0;
         JLabel cpLabel = new JLabel("Code Page:");
-        cpLabel.setForeground(fg);
         cpLabel.setFont(labelFont);
         mainPanel.add(cpLabel, gbc);
         gbc.gridx = 1;
@@ -158,9 +148,8 @@ public class ConnectDialog extends JDialog {
                 break;
             }
         }
-        codePageCombo.setBackground(new Color(45, 45, 45));
-        codePageCombo.setForeground(fg);
         codePageCombo.setFont(new Font(Font.SANS_SERIF, Font.PLAIN, 13));
+        ThemeManager.styleComboBox(codePageCombo);
         mainPanel.add(codePageCombo, gbc);
 
         // TLS / SSL Checkbox
@@ -168,10 +157,8 @@ public class ConnectDialog extends JDialog {
         gbc.gridy = 6;
         gbc.weightx = 1.0;
         tlsCheckBox = new JCheckBox("Enable TLS/SSL");
-        tlsCheckBox.setBackground(new Color(30, 30, 30));
-        tlsCheckBox.setForeground(fg);
+        ThemeManager.styleCheckBox(tlsCheckBox);
         tlsCheckBox.setFont(labelFont);
-        tlsCheckBox.setFocusPainted(false);
         tlsCheckBox.addActionListener(e -> {
             boolean isTls = tlsCheckBox.isSelected();
             verifyCertCheckBox.setEnabled(isTls);
@@ -188,38 +175,31 @@ public class ConnectDialog extends JDialog {
         gbc.gridx = 1;
         gbc.gridy = 7;
         verifyCertCheckBox = new JCheckBox("Verify Server Certificate");
-        verifyCertCheckBox.setBackground(new Color(30, 30, 30));
-        verifyCertCheckBox.setForeground(new Color(160, 160, 160));
+        ThemeManager.styleCheckBox(verifyCertCheckBox);
         verifyCertCheckBox.setFont(new Font(Font.SANS_SERIF, Font.PLAIN, 13));
         verifyCertCheckBox.setSelected(true);
         verifyCertCheckBox.setEnabled(false);
-        verifyCertCheckBox.setFocusPainted(false);
         mainPanel.add(verifyCertCheckBox, gbc);
 
         // TN3270E Checkbox
         gbc.gridx = 1;
         gbc.gridy = 8;
         tn3270eCheckBox = new JCheckBox("Enable TN3270E (Extended 3270)");
-        tn3270eCheckBox.setBackground(new Color(30, 30, 30));
-        tn3270eCheckBox.setForeground(fg);
+        ThemeManager.styleCheckBox(tn3270eCheckBox);
         tn3270eCheckBox.setFont(new Font(Font.SANS_SERIF, Font.PLAIN, 13));
         tn3270eCheckBox.setSelected(haus.nightmare.j3270.config.Settings.getAutoConnectTn3270e());
-        tn3270eCheckBox.setFocusPainted(false);
         mainPanel.add(tn3270eCheckBox, gbc);
 
         // Buttons
-        JPanel buttonPanel = new JPanel(new FlowLayout(FlowLayout.RIGHT));
-        buttonPanel.setBackground(new Color(30, 30, 30));
+        JPanel buttonPanel = new JPanel(new FlowLayout(FlowLayout.RIGHT, 8, 4));
 
         JButton connectBtn = new JButton("Connect");
-        connectBtn.setBackground(new Color(50, 120, 50));
-        connectBtn.setForeground(Color.WHITE);
+        ThemeManager.styleButton(connectBtn, ThemeManager.ButtonVariant.PRIMARY);
         connectBtn.setFont(labelFont);
         connectBtn.addActionListener(e -> onConnect());
 
         JButton cancelBtn = new JButton("Cancel");
-        cancelBtn.setBackground(new Color(60, 60, 60));
-        cancelBtn.setForeground(fg);
+        ThemeManager.styleButton(cancelBtn, ThemeManager.ButtonVariant.CANCEL);
         cancelBtn.setFont(labelFont);
         cancelBtn.addActionListener(e -> {
             confirmed = false;
@@ -235,20 +215,16 @@ public class ConnectDialog extends JDialog {
         mainPanel.add(buttonPanel, gbc);
 
         setContentPane(mainPanel);
+        ThemeManager.applyThemeToWindow(this);
 
         // Enter key triggers connect
         getRootPane().setDefaultButton(connectBtn);
     }
 
-    private JTextField createDarkField(int cols) {
+    private JTextField createField(int cols) {
         JTextField field = new JTextField(cols);
-        field.setBackground(new Color(45, 45, 45));
-        field.setForeground(new Color(200, 200, 200));
-        field.setCaretColor(new Color(200, 200, 200));
         field.setFont(new Font(Font.MONOSPACED, Font.PLAIN, 14));
-        field.setBorder(BorderFactory.createCompoundBorder(
-                BorderFactory.createLineBorder(new Color(60, 60, 60)),
-                BorderFactory.createEmptyBorder(4, 6, 4, 6)));
+        ThemeManager.styleTextField(field);
         return field;
     }
 
diff --git a/j3270/src/main/java/haus/nightmare/j3270/ui/FieldInspectorDialog.java b/j3270/src/main/java/haus/nightmare/j3270/ui/FieldInspectorDialog.java
index 44d55dd..4de1862 100644
--- a/j3270/src/main/java/haus/nightmare/j3270/ui/FieldInspectorDialog.java
+++ b/j3270/src/main/java/haus/nightmare/j3270/ui/FieldInspectorDialog.java
@@ -28,12 +28,6 @@ public class FieldInspectorDialog extends JDialog implements ScreenUpdateListene
     private JTable table;
     private JLabel countLabel;
 
-    private static final Color DARK_BG = new Color(35, 35, 35);
-    private static final Color DARK_FIELD_BG = new Color(45, 45, 45);
-    private static final Color DARK_FG = new Color(220, 220, 220);
-    private static final Color DARK_BORDER = new Color(65, 65, 65);
-    private static final Color DARK_SELECTION = new Color(75, 110, 175);
-
     public FieldInspectorDialog(Frame parent, Telnet3270Client client, TerminalPanel terminalPanel) {
         super(parent, "3270 Presentation Space Field Inspector", false);
         this.client = client;
@@ -61,19 +55,16 @@ public class FieldInspectorDialog extends JDialog implements ScreenUpdateListene
     private void buildUI() {
         JPanel mainPanel = new JPanel(new BorderLayout(8, 8));
         mainPanel.setBorder(new EmptyBorder(10, 10, 10, 10));
-        mainPanel.setBackground(DARK_BG);
 
         // Top info bar
         JPanel topPanel = new JPanel(new BorderLayout());
         topPanel.setOpaque(false);
         countLabel = new JLabel("0 fields detected on screen");
-        countLabel.setForeground(DARK_FG);
         countLabel.setFont(new Font(Font.SANS_SERIF, Font.BOLD, 13));
         topPanel.add(countLabel, BorderLayout.WEST);
 
         JButton refreshBtn = new JButton("Refresh");
-        refreshBtn.setBackground(new Color(55, 55, 55));
-        refreshBtn.setForeground(DARK_FG);
+        ThemeManager.styleButton(refreshBtn, ThemeManager.ButtonVariant.DEFAULT);
         refreshBtn.addActionListener(e -> refreshFields());
         topPanel.add(refreshBtn, BorderLayout.EAST);
         mainPanel.add(topPanel, BorderLayout.NORTH);
@@ -91,18 +82,12 @@ public class FieldInspectorDialog extends JDialog implements ScreenUpdateListene
         };
 
         table = new JTable(tableModel);
-        table.setBackground(DARK_FIELD_BG);
-        table.setForeground(DARK_FG);
-        table.setSelectionBackground(DARK_SELECTION);
-        table.setSelectionForeground(Color.WHITE);
-        table.setGridColor(DARK_BORDER);
+        ThemeManager.styleTable(table);
         table.setFont(new Font(Font.MONOSPACED, Font.PLAIN, 12));
         table.setSelectionMode(ListSelectionModel.SINGLE_SELECTION);
         table.setRowHeight(20);
 
         JTableHeader header = table.getTableHeader();
-        header.setBackground(new Color(50, 50, 50));
-        header.setForeground(DARK_FG);
         header.setFont(new Font(Font.SANS_SERIF, Font.BOLD, 12));
 
         // Column widths
@@ -125,8 +110,7 @@ public class FieldInspectorDialog extends JDialog implements ScreenUpdateListene
         });
 
         JScrollPane scrollPane = new JScrollPane(table);
-        scrollPane.setBorder(new LineBorder(DARK_BORDER));
-        scrollPane.getViewport().setBackground(DARK_FIELD_BG);
+        ThemeManager.styleScrollPane(scrollPane);
         mainPanel.add(scrollPane, BorderLayout.CENTER);
 
         // Bottom panel
@@ -134,8 +118,7 @@ public class FieldInspectorDialog extends JDialog implements ScreenUpdateListene
         bottomPanel.setOpaque(false);
 
         JButton jumpBtn = new JButton("Jump to Selected Field");
-        jumpBtn.setBackground(new Color(50, 100, 160));
-        jumpBtn.setForeground(Color.WHITE);
+        ThemeManager.styleButton(jumpBtn, ThemeManager.ButtonVariant.PRIMARY);
         jumpBtn.addActionListener(e -> {
             int row = table.getSelectedRow();
             if (row >= 0) {
@@ -144,8 +127,7 @@ public class FieldInspectorDialog extends JDialog implements ScreenUpdateListene
         });
 
         JButton closeBtn = new JButton("Close");
-        closeBtn.setBackground(new Color(55, 55, 55));
-        closeBtn.setForeground(DARK_FG);
+        ThemeManager.styleButton(closeBtn, ThemeManager.ButtonVariant.CANCEL);
         closeBtn.addActionListener(e -> dispose());
 
         bottomPanel.add(jumpBtn);
@@ -153,6 +135,7 @@ public class FieldInspectorDialog extends JDialog implements ScreenUpdateListene
         mainPanel.add(bottomPanel, BorderLayout.SOUTH);
 
         setContentPane(mainPanel);
+        ThemeManager.applyThemeToWindow(this);
     }
 
     public synchronized void refreshFields() {
diff --git a/j3270/src/main/java/haus/nightmare/j3270/ui/FindDialog.java b/j3270/src/main/java/haus/nightmare/j3270/ui/FindDialog.java
index b8da128..0668f33 100644
--- a/j3270/src/main/java/haus/nightmare/j3270/ui/FindDialog.java
+++ b/j3270/src/main/java/haus/nightmare/j3270/ui/FindDialog.java
@@ -42,7 +42,6 @@ public class FindDialog extends JDialog {
     private void buildUI() {
         JPanel mainPanel = new JPanel(new BorderLayout(10, 10));
         mainPanel.setBorder(new EmptyBorder(12, 14, 12, 14));
-        mainPanel.setBackground(new Color(35, 35, 35));
 
         // Form
         JPanel formPanel = new JPanel(new GridBagLayout());
@@ -51,14 +50,12 @@ public class FindDialog extends JDialog {
         gbc.insets = new Insets(4, 4, 4, 4);
         gbc.fill = GridBagConstraints.HORIZONTAL;
 
-        Color fg = new Color(220, 220, 220);
         Font labelFont = new Font(Font.SANS_SERIF, Font.PLAIN, 13);
 
         // Search text
         gbc.gridx = 0;
         gbc.gridy = 0;
         JLabel findLabel = new JLabel("Find what:");
-        findLabel.setForeground(fg);
         findLabel.setFont(labelFont);
         formPanel.add(findLabel, gbc);
 
@@ -66,23 +63,16 @@ public class FindDialog extends JDialog {
         gbc.weightx = 1.0;
         searchField = new JTextField(20);
         searchField.setText(lastSearchText);
-        searchField.setBackground(new Color(50, 50, 50));
-        searchField.setForeground(fg);
-        searchField.setCaretColor(fg);
         searchField.setFont(new Font(Font.MONOSPACED, Font.PLAIN, 13));
-        searchField.setBorder(BorderFactory.createCompoundBorder(
-                BorderFactory.createLineBorder(new Color(70, 70, 70)),
-                BorderFactory.createEmptyBorder(3, 6, 3, 6)));
+        ThemeManager.styleTextField(searchField);
         formPanel.add(searchField, gbc);
 
         // Options
         gbc.gridx = 1;
         gbc.gridy = 1;
         matchCaseCheck = new JCheckBox("Match case", lastMatchCase);
-        matchCaseCheck.setForeground(fg);
-        matchCaseCheck.setOpaque(false);
+        ThemeManager.styleCheckBox(matchCaseCheck);
         matchCaseCheck.setFont(labelFont);
-        matchCaseCheck.setFocusPainted(false);
         formPanel.add(matchCaseCheck, gbc);
 
         // Direction
@@ -91,16 +81,11 @@ public class FindDialog extends JDialog {
         JPanel dirPanel = new JPanel(new FlowLayout(FlowLayout.LEFT, 0, 0));
         dirPanel.setOpaque(false);
         JLabel dirLabel = new JLabel("Direction: ");
-        dirLabel.setForeground(fg);
         dirLabel.setFont(labelFont);
         forwardRadio = new JRadioButton("Down", lastForward);
         backwardRadio = new JRadioButton("Up", !lastForward);
-        forwardRadio.setForeground(fg);
-        backwardRadio.setForeground(fg);
-        forwardRadio.setOpaque(false);
-        backwardRadio.setOpaque(false);
-        forwardRadio.setFocusPainted(false);
-        backwardRadio.setFocusPainted(false);
+        ThemeManager.styleRadioButton(forwardRadio);
+        ThemeManager.styleRadioButton(backwardRadio);
 
         ButtonGroup bg = new ButtonGroup();
         bg.add(forwardRadio);
@@ -116,7 +101,7 @@ public class FindDialog extends JDialog {
         gbc.gridy = 3;
         gbc.gridwidth = 2;
         statusLabel = new JLabel(" ");
-        statusLabel.setForeground(new Color(255, 120, 120));
+        statusLabel.setForeground(ThemeManager.getOiaFgAlert());
         statusLabel.setFont(new Font(Font.SANS_SERIF, Font.PLAIN, 12));
         formPanel.add(statusLabel, gbc);
 
@@ -127,14 +112,12 @@ public class FindDialog extends JDialog {
         buttonPanel.setOpaque(false);
 
         JButton findNextBtn = new JButton("Find Next");
-        findNextBtn.setBackground(new Color(60, 63, 65));
-        findNextBtn.setForeground(fg);
+        ThemeManager.styleButton(findNextBtn, ThemeManager.ButtonVariant.PRIMARY);
         findNextBtn.setFont(labelFont);
         findNextBtn.addActionListener(e -> findNext());
 
         JButton closeBtn = new JButton("Close");
-        closeBtn.setBackground(new Color(60, 63, 65));
-        closeBtn.setForeground(fg);
+        ThemeManager.styleButton(closeBtn, ThemeManager.ButtonVariant.CANCEL);
         closeBtn.setFont(labelFont);
         closeBtn.addActionListener(e -> dispose());
 
@@ -144,6 +127,7 @@ public class FindDialog extends JDialog {
         mainPanel.add(buttonPanel, BorderLayout.SOUTH);
 
         setContentPane(mainPanel);
+        ThemeManager.applyThemeToWindow(this);
         getRootPane().setDefaultButton(findNextBtn);
 
         searchField.addKeyListener(new KeyAdapter() {
diff --git a/j3270/src/main/java/haus/nightmare/j3270/ui/HostDirectoryDialog.java b/j3270/src/main/java/haus/nightmare/j3270/ui/HostDirectoryDialog.java
index b009864..2f462d0 100644
--- a/j3270/src/main/java/haus/nightmare/j3270/ui/HostDirectoryDialog.java
+++ b/j3270/src/main/java/haus/nightmare/j3270/ui/HostDirectoryDialog.java
@@ -49,9 +49,7 @@ public class HostDirectoryDialog extends JDialog {
     private void buildUI(String initialQuery) {
         JPanel mainPanel = new JPanel(new BorderLayout(10, 10));
         mainPanel.setBorder(new EmptyBorder(12, 12, 12, 12));
-        mainPanel.setBackground(new Color(35, 35, 35));
 
-        Color fg = new Color(220, 220, 220);
         Font font = new Font(Font.SANS_SERIF, Font.PLAIN, 13);
 
         // Top Query bar
@@ -62,7 +60,6 @@ public class HostDirectoryDialog extends JDialog {
         gbc.fill = GridBagConstraints.HORIZONTAL;
 
         JLabel envLabel = new JLabel("System:");
-        envLabel.setForeground(fg);
         envLabel.setFont(font);
         topPanel.add(envLabel, gbc);
 
@@ -70,33 +67,25 @@ public class HostDirectoryDialog extends JDialog {
         hostTypeCombo = new JComboBox<>(new FTConfig.HostType[]{FTConfig.HostType.TSO, FTConfig.HostType.CMS});
         if (initialHostType == FTConfig.HostType.CMS) hostTypeCombo.setSelectedItem(FTConfig.HostType.CMS);
         else hostTypeCombo.setSelectedItem(FTConfig.HostType.TSO);
-        hostTypeCombo.setBackground(new Color(50, 50, 50));
-        hostTypeCombo.setForeground(fg);
+        ThemeManager.styleComboBox(hostTypeCombo);
         topPanel.add(hostTypeCombo, gbc);
 
         gbc.gridx = 2;
         JLabel queryLabel = new JLabel("Query Pattern / Text:");
-        queryLabel.setForeground(fg);
         queryLabel.setFont(font);
         topPanel.add(queryLabel, gbc);
 
         gbc.gridx = 3;
         gbc.weightx = 1.0;
         queryField = new JTextField(initialQuery != null ? initialQuery : "", 16);
-        queryField.setBackground(new Color(50, 50, 50));
-        queryField.setForeground(fg);
-        queryField.setCaretColor(fg);
         queryField.setFont(new Font(Font.MONOSPACED, Font.PLAIN, 13));
-        queryField.setBorder(BorderFactory.createCompoundBorder(
-                new LineBorder(new Color(70, 70, 70)),
-                new EmptyBorder(3, 5, 3, 5)));
+        ThemeManager.styleTextField(queryField);
         topPanel.add(queryField, gbc);
 
         gbc.gridx = 4;
         gbc.weightx = 0;
         JButton parseBtn = new JButton("Query / Parse");
-        parseBtn.setBackground(new Color(55, 55, 55));
-        parseBtn.setForeground(fg);
+        ThemeManager.styleButton(parseBtn, ThemeManager.ButtonVariant.DEFAULT);
         parseBtn.setFont(font);
         parseBtn.addActionListener(e -> runQuery());
         topPanel.add(parseBtn, gbc);
@@ -106,18 +95,12 @@ public class HostDirectoryDialog extends JDialog {
         // Table
         tableModel = new DefaultTableModel();
         table = new JTable(tableModel);
-        table.setBackground(new Color(45, 45, 45));
-        table.setForeground(fg);
-        table.setSelectionBackground(new Color(75, 110, 175));
-        table.setSelectionForeground(Color.WHITE);
-        table.setGridColor(new Color(65, 65, 65));
+        ThemeManager.styleTable(table);
         table.setFont(new Font(Font.MONOSPACED, Font.PLAIN, 12));
         table.setSelectionMode(ListSelectionModel.SINGLE_SELECTION);
         table.setRowHeight(20);
 
         JTableHeader header = table.getTableHeader();
-        header.setBackground(new Color(50, 50, 50));
-        header.setForeground(fg);
         header.setFont(new Font(Font.SANS_SERIF, Font.BOLD, 12));
 
         table.addMouseListener(new MouseAdapter() {
@@ -130,8 +113,7 @@ public class HostDirectoryDialog extends JDialog {
         });
 
         JScrollPane scrollPane = new JScrollPane(table);
-        scrollPane.setBorder(new LineBorder(new Color(65, 65, 65)));
-        scrollPane.getViewport().setBackground(new Color(45, 45, 45));
+        ThemeManager.styleScrollPane(scrollPane);
         mainPanel.add(scrollPane, BorderLayout.CENTER);
 
         // Bottom
@@ -139,7 +121,7 @@ public class HostDirectoryDialog extends JDialog {
         bottomPanel.setOpaque(false);
 
         statusLabel = new JLabel("Enter a dataset pattern or parse active screen.");
-        statusLabel.setForeground(new Color(170, 170, 170));
+        statusLabel.setForeground(ThemeManager.getFgMuted());
         statusLabel.setFont(new Font(Font.SANS_SERIF, Font.PLAIN, 12));
         bottomPanel.add(statusLabel, BorderLayout.WEST);
 
@@ -147,20 +129,17 @@ public class HostDirectoryDialog extends JDialog {
         btnPanel.setOpaque(false);
 
         JButton pasteScreenBtn = new JButton("Parse Current Screen");
-        pasteScreenBtn.setBackground(new Color(50, 50, 50));
-        pasteScreenBtn.setForeground(fg);
+        ThemeManager.styleButton(pasteScreenBtn, ThemeManager.ButtonVariant.DEFAULT);
         pasteScreenBtn.setFont(font);
         pasteScreenBtn.addActionListener(e -> parseCurrentScreen());
 
         JButton selectBtn = new JButton("Select Dataset");
-        selectBtn.setBackground(new Color(50, 120, 50));
-        selectBtn.setForeground(Color.WHITE);
+        ThemeManager.styleButton(selectBtn, ThemeManager.ButtonVariant.PRIMARY);
         selectBtn.setFont(font);
         selectBtn.addActionListener(e -> onConfirmSelection());
 
         JButton cancelBtn = new JButton("Cancel");
-        cancelBtn.setBackground(new Color(60, 60, 60));
-        cancelBtn.setForeground(fg);
+        ThemeManager.styleButton(cancelBtn, ThemeManager.ButtonVariant.CANCEL);
         cancelBtn.setFont(font);
         cancelBtn.addActionListener(e -> {
             confirmed = false;
@@ -176,6 +155,7 @@ public class HostDirectoryDialog extends JDialog {
         mainPanel.add(bottomPanel, BorderLayout.SOUTH);
 
         setContentPane(mainPanel);
+        ThemeManager.applyThemeToWindow(this);
 
         // Initial setup
         setupTableColumns();
diff --git a/j3270/src/main/java/haus/nightmare/j3270/ui/PrinterSessionDialog.java b/j3270/src/main/java/haus/nightmare/j3270/ui/PrinterSessionDialog.java
index f1393fd..8180ed5 100644
--- a/j3270/src/main/java/haus/nightmare/j3270/ui/PrinterSessionDialog.java
+++ b/j3270/src/main/java/haus/nightmare/j3270/ui/PrinterSessionDialog.java
@@ -45,10 +45,6 @@ public class PrinterSessionDialog extends JDialog implements PrintSessionListene
     // Spool Display
     private JTextArea spoolArea;
 
-    private static final Color DARK_BG = new Color(35, 35, 35);
-    private static final Color DARK_FG = new Color(220, 220, 220);
-    private static final Color DARK_FIELD_BG = new Color(45, 45, 45);
-
     public PrinterSessionDialog(Frame parent, String defaultHost, int defaultPort, boolean defaultTls) {
         super(parent, "IBM 3287 Printer Session Manager", false);
         this.parent = parent;
@@ -65,14 +61,11 @@ public class PrinterSessionDialog extends JDialog implements PrintSessionListene
     private void buildUI() {
         JPanel mainPanel = new JPanel(new BorderLayout(10, 10));
         mainPanel.setBorder(new EmptyBorder(12, 14, 12, 14));
-        mainPanel.setBackground(DARK_BG);
 
         // Top: Configuration Panel
         JPanel topPanel = new JPanel(new GridBagLayout());
         topPanel.setOpaque(false);
-        topPanel.setBorder(BorderFactory.createTitledBorder(
-                new LineBorder(new Color(65, 65, 65)), "Printer Session Configuration"));
-        ((TitledBorder) topPanel.getBorder()).setTitleColor(DARK_FG);
+        topPanel.setBorder(ThemeManager.createTitledBorder("Printer Session Configuration"));
 
         GridBagConstraints gbc = new GridBagConstraints();
         gbc.insets = new Insets(3, 4, 3, 4);
@@ -83,60 +76,59 @@ public class PrinterSessionDialog extends JDialog implements PrintSessionListene
         // Host / Port
         gbc.gridx = 0; gbc.gridy = 0;
         JLabel hLbl = new JLabel("Host:");
-        hLbl.setForeground(DARK_FG); hLbl.setFont(labelFont);
+        hLbl.setFont(labelFont);
         topPanel.add(hLbl, gbc);
 
         gbc.gridx = 1; gbc.weightx = 1.0;
-        hostField = createDarkField(config.getHost() != null ? config.getHost() : "localhost", 14);
+        hostField = createField(config.getHost() != null ? config.getHost() : "localhost", 14);
         topPanel.add(hostField, gbc);
 
         gbc.gridx = 2; gbc.weightx = 0;
         JLabel pLbl = new JLabel("Port:");
-        pLbl.setForeground(DARK_FG); pLbl.setFont(labelFont);
+        pLbl.setFont(labelFont);
         topPanel.add(pLbl, gbc);
 
         gbc.gridx = 3; gbc.weightx = 0.5;
-        portField = createDarkField(String.valueOf(config.getPort()), 5);
+        portField = createField(String.valueOf(config.getPort()), 5);
         topPanel.add(portField, gbc);
 
         // Printer LU / Display LU
         gbc.gridx = 0; gbc.gridy = 1; gbc.weightx = 0;
         JLabel pluLbl = new JLabel("Printer LU:");
-        pluLbl.setForeground(DARK_FG); pluLbl.setFont(labelFont);
+        pluLbl.setFont(labelFont);
         topPanel.add(pluLbl, gbc);
 
         gbc.gridx = 1; gbc.weightx = 1.0;
-        printerLuField = createDarkField("", 10);
+        printerLuField = createField("", 10);
         topPanel.add(printerLuField, gbc);
 
         gbc.gridx = 2; gbc.weightx = 0;
         JLabel assocLbl = new JLabel("Assoc LU:");
-        assocLbl.setForeground(DARK_FG); assocLbl.setFont(labelFont);
+        assocLbl.setFont(labelFont);
         topPanel.add(assocLbl, gbc);
 
         gbc.gridx = 3; gbc.weightx = 0.5;
-        displayLuField = createDarkField("", 10);
+        displayLuField = createField("", 10);
         topPanel.add(displayLuField, gbc);
 
         // CodePage & TLS
         gbc.gridx = 0; gbc.gridy = 2; gbc.weightx = 0;
         JLabel cpLbl = new JLabel("CodePage:");
-        cpLbl.setForeground(DARK_FG); cpLbl.setFont(labelFont);
+        cpLbl.setFont(labelFont);
         topPanel.add(cpLbl, gbc);
 
         gbc.gridx = 1; gbc.weightx = 1.0;
         codePageCombo = new JComboBox<>(new String[]{"037", "1047", "500", "273", "277", "278", "280", "284", "285", "297", "870", "1140"});
-        codePageCombo.setBackground(DARK_FIELD_BG);
-        codePageCombo.setForeground(DARK_FG);
+        ThemeManager.styleComboBox(codePageCombo);
         topPanel.add(codePageCombo, gbc);
 
         gbc.gridx = 2; gbc.gridwidth = 2;
         JPanel tlsPanel = new JPanel(new FlowLayout(FlowLayout.LEFT, 4, 0));
         tlsPanel.setOpaque(false);
         tlsCheck = new JCheckBox("TLS/SSL", config.isUseTls());
-        tlsCheck.setOpaque(false); tlsCheck.setForeground(DARK_FG); tlsCheck.setFocusPainted(false);
+        ThemeManager.styleCheckBox(tlsCheck);
         verifyCertCheck = new JCheckBox("Verify Cert", config.isTlsVerifyCert());
-        verifyCertCheck.setOpaque(false); verifyCertCheck.setForeground(DARK_FG); verifyCertCheck.setFocusPainted(false);
+        ThemeManager.styleCheckBox(verifyCertCheck);
         tlsPanel.add(tlsCheck);
         tlsPanel.add(verifyCertCheck);
         topPanel.add(tlsPanel, gbc);
@@ -144,23 +136,22 @@ public class PrinterSessionDialog extends JDialog implements PrintSessionListene
         // Destination Type & Target
         gbc.gridx = 0; gbc.gridy = 3; gbc.gridwidth = 1;
         JLabel destLbl = new JLabel("Destination:");
-        destLbl.setForeground(DARK_FG); destLbl.setFont(labelFont);
+        destLbl.setFont(labelFont);
         topPanel.add(destLbl, gbc);
 
         gbc.gridx = 1;
         destinationCombo = new JComboBox<>(PrinterConfig.DestinationType.values());
         destinationCombo.setSelectedItem(PrinterConfig.DestinationType.MEMORY);
-        destinationCombo.setBackground(DARK_FIELD_BG);
-        destinationCombo.setForeground(DARK_FG);
+        ThemeManager.styleComboBox(destinationCombo);
         topPanel.add(destinationCombo, gbc);
 
         gbc.gridx = 2;
         JLabel tgtLbl = new JLabel("Target Path:");
-        tgtLbl.setForeground(DARK_FG); tgtLbl.setFont(labelFont);
+        tgtLbl.setFont(labelFont);
         topPanel.add(tgtLbl, gbc);
 
         gbc.gridx = 3;
-        targetField = createDarkField("printer_output.txt", 12);
+        targetField = createField("printer_output.txt", 12);
         topPanel.add(targetField, gbc);
 
         // Connect / Disconnect Buttons
@@ -169,13 +160,11 @@ public class PrinterSessionDialog extends JDialog implements PrintSessionListene
         connBtnPan.setOpaque(false);
 
         connectBtn = new JButton("Start Printer Session");
-        connectBtn.setBackground(new Color(50, 120, 50));
-        connectBtn.setForeground(Color.WHITE);
+        ThemeManager.styleButton(connectBtn, ThemeManager.ButtonVariant.PRIMARY);
         connectBtn.addActionListener(e -> startPrinterSession());
 
         disconnectBtn = new JButton("Stop Session");
-        disconnectBtn.setBackground(new Color(120, 50, 50));
-        disconnectBtn.setForeground(Color.WHITE);
+        ThemeManager.styleButton(disconnectBtn, ThemeManager.ButtonVariant.DANGER);
         disconnectBtn.setEnabled(false);
         disconnectBtn.addActionListener(e -> stopPrinterSession());
 
@@ -188,9 +177,7 @@ public class PrinterSessionDialog extends JDialog implements PrintSessionListene
         // Center: Spool Area & Status
         JPanel centerPanel = new JPanel(new BorderLayout(6, 6));
         centerPanel.setOpaque(false);
-        centerPanel.setBorder(BorderFactory.createTitledBorder(
-                new LineBorder(new Color(65, 65, 65)), "Printer Spool & Status"));
-        ((TitledBorder) centerPanel.getBorder()).setTitleColor(DARK_FG);
+        centerPanel.setBorder(ThemeManager.createTitledBorder("Printer Spool & Status"));
 
         // Status Header
         JPanel statusHeader = new JPanel(new GridLayout(1, 4, 10, 0));
@@ -198,19 +185,16 @@ public class PrinterSessionDialog extends JDialog implements PrintSessionListene
         statusHeader.setBorder(new EmptyBorder(0, 4, 4, 4));
 
         statusLabel = new JLabel("Status: Disconnected");
-        statusLabel.setForeground(new Color(180, 180, 180));
+        statusLabel.setForeground(ThemeManager.getFgMuted());
         statusLabel.setFont(labelFont);
 
         sessionTypeLabel = new JLabel("Session: -");
-        sessionTypeLabel.setForeground(DARK_FG);
         sessionTypeLabel.setFont(labelFont);
 
         pagesLabel = new JLabel("Pages: 0");
-        pagesLabel.setForeground(DARK_FG);
         pagesLabel.setFont(labelFont);
 
         bytesLabel = new JLabel("Bytes: 0");
-        bytesLabel.setForeground(DARK_FG);
         bytesLabel.setFont(labelFont);
 
         statusHeader.add(statusLabel);
@@ -221,14 +205,12 @@ public class PrinterSessionDialog extends JDialog implements PrintSessionListene
 
         // Spool text area
         spoolArea = new JTextArea();
-        spoolArea.setBackground(new Color(25, 25, 25));
-        spoolArea.setForeground(new Color(100, 255, 100));
-        spoolArea.setCaretColor(Color.WHITE);
         spoolArea.setFont(new Font(Font.MONOSPACED, Font.PLAIN, 12));
         spoolArea.setEditable(false);
+        ThemeManager.styleTextArea(spoolArea);
 
         JScrollPane spoolScroll = new JScrollPane(spoolArea);
-        spoolScroll.setBorder(new LineBorder(new Color(60, 60, 60)));
+        ThemeManager.styleScrollPane(spoolScroll);
         centerPanel.add(spoolScroll, BorderLayout.CENTER);
 
         mainPanel.add(centerPanel, BorderLayout.CENTER);
@@ -238,8 +220,7 @@ public class PrinterSessionDialog extends JDialog implements PrintSessionListene
         bottomPanel.setOpaque(false);
 
         JButton clearSpoolBtn = new JButton("Clear Spool");
-        clearSpoolBtn.setBackground(new Color(50, 50, 50));
-        clearSpoolBtn.setForeground(DARK_FG);
+        ThemeManager.styleButton(clearSpoolBtn, ThemeManager.ButtonVariant.DEFAULT);
         clearSpoolBtn.addActionListener(e -> {
             spoolArea.setText("");
             if (printerSession != null && printerSession.getPD() != null) {
@@ -250,18 +231,15 @@ public class PrinterSessionDialog extends JDialog implements PrintSessionListene
         });
 
         JButton saveSpoolBtn = new JButton("Save Spool As...");
-        saveSpoolBtn.setBackground(new Color(50, 50, 50));
-        saveSpoolBtn.setForeground(DARK_FG);
+        ThemeManager.styleButton(saveSpoolBtn, ThemeManager.ButtonVariant.DEFAULT);
         saveSpoolBtn.addActionListener(e -> saveSpool());
 
         JButton printSpoolBtn = new JButton("Print Spool...");
-        printSpoolBtn.setBackground(new Color(50, 100, 160));
-        printSpoolBtn.setForeground(Color.WHITE);
+        ThemeManager.styleButton(printSpoolBtn, ThemeManager.ButtonVariant.DEFAULT);
         printSpoolBtn.addActionListener(e -> printSpool());
 
         JButton closeBtn = new JButton("Close");
-        closeBtn.setBackground(new Color(60, 60, 60));
-        closeBtn.setForeground(DARK_FG);
+        ThemeManager.styleButton(closeBtn, ThemeManager.ButtonVariant.CANCEL);
         closeBtn.addActionListener(e -> dispose());
 
         bottomPanel.add(clearSpoolBtn);
@@ -273,17 +251,13 @@ public class PrinterSessionDialog extends JDialog implements PrintSessionListene
         mainPanel.add(bottomPanel, BorderLayout.SOUTH);
 
         setContentPane(mainPanel);
+        ThemeManager.applyThemeToWindow(this);
     }
 
-    private JTextField createDarkField(String text, int cols) {
+    private JTextField createField(String text, int cols) {
         JTextField tf = new JTextField(text, cols);
-        tf.setBackground(DARK_FIELD_BG);
-        tf.setForeground(DARK_FG);
-        tf.setCaretColor(DARK_FG);
         tf.setFont(new Font(Font.MONOSPACED, Font.PLAIN, 12));
-        tf.setBorder(BorderFactory.createCompoundBorder(
-                new LineBorder(new Color(65, 65, 65)),
-                new EmptyBorder(2, 4, 2, 4)));
+        ThemeManager.styleTextField(tf);
         return tf;
     }
 
diff --git a/j3270/src/main/java/haus/nightmare/j3270/ui/ScriptDialog.java b/j3270/src/main/java/haus/nightmare/j3270/ui/ScriptDialog.java
index 9a3b376..ac95f63 100644
--- a/j3270/src/main/java/haus/nightmare/j3270/ui/ScriptDialog.java
+++ b/j3270/src/main/java/haus/nightmare/j3270/ui/ScriptDialog.java
@@ -34,9 +34,7 @@ public class ScriptDialog extends JDialog {
     private void buildUI() {
         JPanel mainPanel = new JPanel(new BorderLayout(10, 10));
         mainPanel.setBorder(new EmptyBorder(12, 14, 12, 14));
-        mainPanel.setBackground(new Color(35, 35, 35));
 
-        Color fg = new Color(220, 220, 220);
         Font labelFont = new Font(Font.SANS_SERIF, Font.PLAIN, 13);
 
         // Header
@@ -44,31 +42,24 @@ public class ScriptDialog extends JDialog {
         topPanel.setOpaque(false);
         JLabel descLabel = new JLabel("<html>Compose keystrokes and ECL bracketed mnemonics to stream to the mainframe.<br>"
                 + "Example: <code>TSO[enter]USER[tab]PASSWORD[enter]</code> or <code>[pf3][clear]</code></html>");
-        descLabel.setForeground(new Color(180, 180, 180));
         descLabel.setFont(labelFont);
         topPanel.add(descLabel, BorderLayout.CENTER);
         mainPanel.add(topPanel, BorderLayout.NORTH);
 
         // Script area
         scriptArea = new JTextArea();
-        scriptArea.setBackground(new Color(25, 25, 25));
-        scriptArea.setForeground(new Color(50, 205, 50));
-        scriptArea.setCaretColor(Color.WHITE);
         scriptArea.setFont(new Font(Font.MONOSPACED, Font.PLAIN, 13));
         scriptArea.setLineWrap(true);
         scriptArea.setWrapStyleWord(false);
+        ThemeManager.styleTextArea(scriptArea);
 
         JScrollPane scrollPane = new JScrollPane(scriptArea);
-        scrollPane.setBorder(BorderFactory.createCompoundBorder(
-                new LineBorder(new Color(60, 60, 60)),
-                new EmptyBorder(2, 2, 2, 2)));
+        ThemeManager.styleScrollPane(scrollPane);
 
         // Mnemonic helper buttons
         JPanel tokenPanel = new JPanel(new WrapLayout(FlowLayout.LEFT, 4, 4));
         tokenPanel.setOpaque(false);
-        tokenPanel.setBorder(BorderFactory.createTitledBorder(
-                new LineBorder(new Color(60, 60, 60)), "Insert Keystroke Token"));
-        ((TitledBorder) tokenPanel.getBorder()).setTitleColor(new Color(180, 180, 180));
+        tokenPanel.setBorder(ThemeManager.createTitledBorder("Insert Keystroke Token"));
 
         String[] tokens = {
             "[enter]", "[tab]", "[backtab]", "[clear]", "[reset]",
@@ -84,8 +75,7 @@ public class ScriptDialog extends JDialog {
         for (String token : tokens) {
             JButton btn = new JButton(token);
             btn.setFont(new Font(Font.MONOSPACED, Font.PLAIN, 11));
-            btn.setBackground(new Color(50, 50, 50));
-            btn.setForeground(fg);
+            ThemeManager.styleButton(btn, ThemeManager.ButtonVariant.DEFAULT);
             btn.setFocusable(false);
             btn.setMargin(new Insets(2, 4, 2, 4));
             btn.addActionListener(e -> insertToken(token));
@@ -103,7 +93,7 @@ public class ScriptDialog extends JDialog {
         bottomPanel.setOpaque(false);
 
         statusLabel = new JLabel("Ready");
-        statusLabel.setForeground(new Color(160, 160, 160));
+        statusLabel.setForeground(ThemeManager.getFgMuted());
         statusLabel.setFont(new Font(Font.SANS_SERIF, Font.PLAIN, 12));
         bottomPanel.add(statusLabel, BorderLayout.WEST);
 
@@ -111,26 +101,22 @@ public class ScriptDialog extends JDialog {
         buttonPanel.setOpaque(false);
 
         JButton loadBtn = new JButton("Load Script...");
-        loadBtn.setBackground(new Color(50, 50, 50));
-        loadBtn.setForeground(fg);
+        ThemeManager.styleButton(loadBtn, ThemeManager.ButtonVariant.DEFAULT);
         loadBtn.setFont(labelFont);
         loadBtn.addActionListener(e -> loadScript());
 
         JButton saveBtn = new JButton("Save Script...");
-        saveBtn.setBackground(new Color(50, 50, 50));
-        saveBtn.setForeground(fg);
+        ThemeManager.styleButton(saveBtn, ThemeManager.ButtonVariant.DEFAULT);
         saveBtn.setFont(labelFont);
         saveBtn.addActionListener(e -> saveScript());
 
         JButton runBtn = new JButton("Execute");
-        runBtn.setBackground(new Color(50, 120, 50));
-        runBtn.setForeground(Color.WHITE);
+        ThemeManager.styleButton(runBtn, ThemeManager.ButtonVariant.PRIMARY);
         runBtn.setFont(labelFont);
         runBtn.addActionListener(e -> executeScript());
 
         JButton closeBtn = new JButton("Close");
-        closeBtn.setBackground(new Color(60, 60, 60));
-        closeBtn.setForeground(fg);
+        ThemeManager.styleButton(closeBtn, ThemeManager.ButtonVariant.CANCEL);
         closeBtn.setFont(labelFont);
         closeBtn.addActionListener(e -> dispose());
 
@@ -144,6 +130,7 @@ public class ScriptDialog extends JDialog {
         mainPanel.add(bottomPanel, BorderLayout.SOUTH);
 
         setContentPane(mainPanel);
+        ThemeManager.applyThemeToWindow(this);
     }
 
     private void insertToken(String token) {
diff --git a/j3270/src/main/java/haus/nightmare/j3270/ui/SettingsDialog.java b/j3270/src/main/java/haus/nightmare/j3270/ui/SettingsDialog.java
index 894db5e..e3f02c0 100644
--- a/j3270/src/main/java/haus/nightmare/j3270/ui/SettingsDialog.java
+++ b/j3270/src/main/java/haus/nightmare/j3270/ui/SettingsDialog.java
@@ -19,16 +19,8 @@ public class SettingsDialog extends JDialog {
 
     private final J3270App parentApp;
 
-    // Dark theme colors
-    private static final Color DARK_BG = new Color(43, 43, 43);
-    private static final Color DARK_BG_LIGHTER = new Color(55, 55, 55);
-    private static final Color DARK_FG = new Color(224, 224, 224);
-    private static final Color DARK_BORDER = new Color(70, 70, 70);
-    private static final Color DARK_SELECTION = new Color(75, 110, 175);
-    private static final Color DARK_BUTTON_BG = new Color(60, 63, 65);
-    private static final Color DARK_FIELD_BG = new Color(50, 50, 50);
-
     // Appearance tab
+    private JComboBox<UITheme> uiThemeBox;
     private JComboBox<String> fontBox;
     private JSpinner fontSizeSpinner;
     private JComboBox<haus.nightmare.lib3270j.graphics.GraphicsMode> graphicsModeBox;
@@ -51,22 +43,30 @@ public class SettingsDialog extends JDialog {
         this.parentApp = parent;
 
         initComponents();
-        setSize(550, 450);
+        setSize(560, 480);
         setLocationRelativeTo(parent);
     }
 
     private void initComponents() {
         JTabbedPane tabbedPane = new JTabbedPane();
+        ThemeManager.styleTabbedPane(tabbedPane);
 
         tabbedPane.addTab("Appearance", createAppearancePanel());
         tabbedPane.addTab("Behavior", createBehaviorPanel());
         tabbedPane.addTab("Advanced", createAdvancedPanel());
 
-        JPanel buttonPanel = new JPanel(new FlowLayout(FlowLayout.RIGHT));
+        JPanel buttonPanel = new JPanel(new FlowLayout(FlowLayout.RIGHT, 8, 8));
         JButton btnExport = new JButton("Export Config...");
-        JButton btnOk = new JButton("OK");
+        ThemeManager.styleButton(btnExport, ThemeManager.ButtonVariant.DEFAULT);
+
         JButton btnApply = new JButton("Apply");
+        ThemeManager.styleButton(btnApply, ThemeManager.ButtonVariant.DEFAULT);
+
         JButton btnCancel = new JButton("Cancel");
+        ThemeManager.styleButton(btnCancel, ThemeManager.ButtonVariant.CANCEL);
+
+        JButton btnOk = new JButton("OK");
+        ThemeManager.styleButton(btnOk, ThemeManager.ButtonVariant.PRIMARY);
 
         btnExport.addActionListener((ActionEvent e) -> {
             exportConfig();
@@ -96,132 +96,11 @@ public class SettingsDialog extends JDialog {
         getContentPane().add(tabbedPane, BorderLayout.CENTER);
         getContentPane().add(buttonPanel, BorderLayout.SOUTH);
 
-        // Apply dark theme to all components for cross-platform readability
-        applyDarkTheme(getContentPane());
-        applyDarkTheme(tabbedPane);
-        applyDarkTheme(buttonPanel);
-        getContentPane().setBackground(DARK_BG);
+        ThemeManager.applyThemeToWindow(this);
     }
 
-    // ========== Dark Theme Utility ==========
-
-    /**
-     * Recursively apply dark theme to a component and all its children.
-     * Ensures the Settings dialog is readable on Windows, Linux, and macOS.
-     */
     private void applyDarkTheme(Component comp) {
-        if (comp instanceof JTabbedPane) {
-            JTabbedPane tp = (JTabbedPane) comp;
-            tp.setBackground(DARK_BG);
-            tp.setForeground(DARK_FG);
-            for (int i = 0; i < tp.getTabCount(); i++) {
-                applyDarkTheme(tp.getComponentAt(i));
-            }
-            return;
-        }
-
-        if (comp instanceof JTable) {
-            JTable table = (JTable) comp;
-            table.setBackground(DARK_FIELD_BG);
-            table.setForeground(DARK_FG);
-            table.setSelectionBackground(DARK_SELECTION);
-            table.setSelectionForeground(Color.WHITE);
-            table.setGridColor(DARK_BORDER);
-            JTableHeader header = table.getTableHeader();
-            if (header != null) {
-                header.setBackground(DARK_BG_LIGHTER);
-                header.setForeground(DARK_FG);
-                DefaultTableCellRenderer headerRenderer = new DefaultTableCellRenderer();
-                headerRenderer.setBackground(DARK_BG_LIGHTER);
-                headerRenderer.setForeground(DARK_FG);
-                header.setDefaultRenderer(headerRenderer);
-            }
-            return;
-        }
-
-        if (comp instanceof JScrollPane) {
-            JScrollPane sp = (JScrollPane) comp;
-            sp.setBackground(DARK_BG);
-            sp.getViewport().setBackground(DARK_FIELD_BG);
-            applyDarkTheme(sp.getViewport().getView());
-            return;
-        }
-
-        if (comp instanceof JButton) {
-            JButton btn = (JButton) comp;
-            btn.setBackground(DARK_BUTTON_BG);
-            btn.setForeground(DARK_FG);
-            btn.setFocusPainted(false);
-            btn.setBorder(BorderFactory.createCompoundBorder(
-                new LineBorder(DARK_BORDER, 1),
-                BorderFactory.createEmptyBorder(3, 10, 3, 10)));
-            btn.setOpaque(true);
-            return;
-        }
-
-        if (comp instanceof JComboBox) {
-            JComboBox<?> cb = (JComboBox<?>) comp;
-            cb.setBackground(DARK_FIELD_BG);
-            cb.setForeground(DARK_FG);
-            return;
-        }
-
-        if (comp instanceof JSpinner) {
-            JSpinner sp = (JSpinner) comp;
-            sp.setBackground(DARK_FIELD_BG);
-            sp.setForeground(DARK_FG);
-            JComponent editor = sp.getEditor();
-            if (editor instanceof JSpinner.DefaultEditor) {
-                JTextField tf = ((JSpinner.DefaultEditor) editor).getTextField();
-                tf.setBackground(DARK_FIELD_BG);
-                tf.setForeground(DARK_FG);
-                tf.setCaretColor(DARK_FG);
-            }
-            return;
-        }
-
-        if (comp instanceof JTextField) {
-            JTextField tf = (JTextField) comp;
-            tf.setBackground(DARK_FIELD_BG);
-            tf.setForeground(DARK_FG);
-            tf.setCaretColor(DARK_FG);
-            return;
-        }
-
-        if (comp instanceof JCheckBox) {
-            JCheckBox cb = (JCheckBox) comp;
-            cb.setBackground(DARK_BG);
-            cb.setForeground(DARK_FG);
-            return;
-        }
-
-        if (comp instanceof JLabel) {
-            comp.setForeground(DARK_FG);
-            return;
-        }
-
-        // Generic panel / container
-        // Skip color swatch panels — their background IS the color
-        if (comp instanceof JPanel && "colorSwatch".equals(comp.getName())) {
-            return;
-        }
-        comp.setBackground(DARK_BG);
-        comp.setForeground(DARK_FG);
-
-        if (comp instanceof JPanel) {
-            JPanel panel = (JPanel) comp;
-            // Style titled borders
-            if (panel.getBorder() instanceof TitledBorder) {
-                TitledBorder tb = (TitledBorder) panel.getBorder();
-                tb.setTitleColor(DARK_FG);
-            }
-        }
-
-        if (comp instanceof Container) {
-            for (Component child : ((Container) comp).getComponents()) {
-                applyDarkTheme(child);
-            }
-        }
+        ThemeManager.applyTheme(comp);
     }
 
     // ========== Tab Panels ==========
@@ -232,9 +111,22 @@ public class SettingsDialog extends JDialog {
         gbc.insets = new Insets(10, 10, 10, 10);
         gbc.anchor = GridBagConstraints.WEST;
 
-        // Font family
+        // UI Theme
         gbc.gridx = 0;
         gbc.gridy = 0;
+        JLabel themeLabel = new JLabel("Java UI Theme:");
+        panel.add(themeLabel, gbc);
+
+        uiThemeBox = new JComboBox<>(UITheme.values());
+        uiThemeBox.setSelectedItem(Settings.getJavaUiTheme());
+        gbc.gridx = 1;
+        gbc.fill = GridBagConstraints.HORIZONTAL;
+        panel.add(uiThemeBox, gbc);
+
+        // Font family
+        gbc.gridx = 0;
+        gbc.gridy = 1;
+        gbc.fill = GridBagConstraints.NONE;
         JLabel fontLabel = new JLabel("Terminal Font:");
         panel.add(fontLabel, gbc);
 
@@ -254,7 +146,7 @@ public class SettingsDialog extends JDialog {
 
         // Font size
         gbc.gridx = 0;
-        gbc.gridy = 1;
+        gbc.gridy = 2;
         gbc.fill = GridBagConstraints.NONE;
         JLabel sizeLabel = new JLabel("Font Size:");
         panel.add(sizeLabel, gbc);
@@ -267,7 +159,7 @@ public class SettingsDialog extends JDialog {
 
         // Graphics Mode
         gbc.gridx = 0;
-        gbc.gridy = 2;
+        gbc.gridy = 3;
         gbc.fill = GridBagConstraints.NONE;
         JLabel graphicsLabel = new JLabel("Graphics Mode:");
         panel.add(graphicsLabel, gbc);
@@ -279,7 +171,7 @@ public class SettingsDialog extends JDialog {
         panel.add(graphicsModeBox, gbc);
 
         // Fill remaining space
-        gbc.gridy = 3;
+        gbc.gridy = 4;
         gbc.weighty = 1.0;
         panel.add(Box.createGlue(), gbc);
 
@@ -429,6 +321,7 @@ public class SettingsDialog extends JDialog {
 
         JPanel resetPanel = new JPanel(new FlowLayout(FlowLayout.RIGHT));
         JButton btnResetColors = new JButton("Reset to Defaults");
+        ThemeManager.styleButton(btnResetColors, ThemeManager.ButtonVariant.DEFAULT);
         btnResetColors.addActionListener(e -> {
             for (int i=0; i<16; i++) {
                 tempHostColors[i] = TerminalPanel.DEFAULT_HOST_COLORS[i];
@@ -436,8 +329,6 @@ public class SettingsDialog extends JDialog {
             for (int i=0; i<monoKeys.length; i++) {
                 tempMonoColors.put(monoKeys[i], monoDefs[i]);
             }
-            // Repaint container implicitly handled if we trigger a UI update, 
-            // but for simplicity user can just close/reopen or have it refresh on save
             JOptionPane.showMessageDialog(main, "Colors reset. Click Apply to save.");
         });
         resetPanel.add(btnResetColors);
@@ -498,6 +389,7 @@ public class SettingsDialog extends JDialog {
         }
 
         JTable table = new JTable(keymapModel);
+        ThemeManager.styleTable(table);
         table.setSelectionMode(ListSelectionModel.SINGLE_SELECTION);
         table.setFillsViewportHeight(true);
 
@@ -510,9 +402,8 @@ public class SettingsDialog extends JDialog {
             captureDialog.setSize(320, 100);
             captureDialog.setLocationRelativeTo(this);
             JLabel lbl = new JLabel("Press any key combination now...", SwingConstants.CENTER);
-            lbl.setForeground(DARK_FG);
-            captureDialog.getContentPane().setBackground(DARK_BG);
             captureDialog.add(lbl);
+            ThemeManager.applyThemeToWindow(captureDialog);
             captureDialog.addKeyListener(new KeyAdapter() {
                 @Override
                 public void keyPressed(KeyEvent e) {
@@ -532,6 +423,7 @@ public class SettingsDialog extends JDialog {
 
         // Replace Binding — sets the action to exactly one new key
         JButton btnReplace = new JButton("Replace Binding");
+        ThemeManager.styleButton(btnReplace, ThemeManager.ButtonVariant.DEFAULT);
         btnReplace.addActionListener(e -> {
             int row = table.getSelectedRow();
             if (row < 0) return;
@@ -545,6 +437,7 @@ public class SettingsDialog extends JDialog {
 
         // Add Binding — appends an additional key to the existing binding(s)
         JButton btnAdd = new JButton("Add Binding");
+        ThemeManager.styleButton(btnAdd, ThemeManager.ButtonVariant.DEFAULT);
         btnAdd.addActionListener(e -> {
             int row = table.getSelectedRow();
             if (row < 0) return;
@@ -565,6 +458,7 @@ public class SettingsDialog extends JDialog {
 
         // Remove Last — removes the last comma-separated binding entry
         JButton btnRemoveLast = new JButton("Remove Last");
+        ThemeManager.styleButton(btnRemoveLast, ThemeManager.ButtonVariant.DEFAULT);
         btnRemoveLast.addActionListener(e -> {
             int row = table.getSelectedRow();
             if (row < 0) return;
@@ -585,6 +479,7 @@ public class SettingsDialog extends JDialog {
 
         // Unbind All — clears all bindings for the action
         JButton btnUnbind = new JButton("Unbind All");
+        ThemeManager.styleButton(btnUnbind, ThemeManager.ButtonVariant.DEFAULT);
         btnUnbind.addActionListener(e -> {
             int row = table.getSelectedRow();
             if (row < 0) return;
@@ -596,6 +491,7 @@ public class SettingsDialog extends JDialog {
 
         // Reset Keymaps — restore all defaults
         JButton btnReset = new JButton("Reset All");
+        ThemeManager.styleButton(btnReset, ThemeManager.ButtonVariant.DEFAULT);
         btnReset.addActionListener(e -> {
             for (int row = 0; row < keymapModel.getRowCount(); row++) {
                 String action = (String) keymapModel.getValueAt(row, 0);
@@ -628,6 +524,12 @@ public class SettingsDialog extends JDialog {
     private boolean applySettings() {
         try {
             // Apply Appearance
+            UITheme selectedTheme = (UITheme) uiThemeBox.getSelectedItem();
+            if (selectedTheme != null) {
+                Settings.setJavaUiTheme(selectedTheme);
+                ThemeManager.setTheme(selectedTheme);
+            }
+
             String fontFam = (String) fontBox.getSelectedItem();
             if (fontFam != null) {
                 Settings.setFontFamily(fontFam);
@@ -668,6 +570,7 @@ public class SettingsDialog extends JDialog {
             }
 
             parentApp.getTerminalPanel().reloadSettings();
+            ThemeManager.applyThemeToWindow(this);
 
             return true;
         } catch (Exception e) {
diff --git a/j3270/src/main/java/haus/nightmare/j3270/ui/StatusBar.java b/j3270/src/main/java/haus/nightmare/j3270/ui/StatusBar.java
index 3329a2e..dba72ca 100644
--- a/j3270/src/main/java/haus/nightmare/j3270/ui/StatusBar.java
+++ b/j3270/src/main/java/haus/nightmare/j3270/ui/StatusBar.java
@@ -26,29 +26,22 @@ public class StatusBar extends JPanel {
     private Telnet3270Client client;
     private TerminalPanel terminalPanel;
 
-    // OIA colors
-    private static final Color OIA_BG = new Color(20, 20, 20);
-    private static final Color OIA_FG = new Color(50, 205, 50);
-    private static final Color OIA_DIM = new Color(80, 80, 80);
-    private static final Color OIA_ALERT = new Color(255, 80, 80);
-    private static final Color OIA_WARN = new Color(255, 200, 80);
-
     public StatusBar() {
         setLayout(new BoxLayout(this, BoxLayout.X_AXIS));
-        setBackground(OIA_BG);
-        setBorder(BorderFactory.createMatteBorder(1, 0, 0, 0, new Color(40, 40, 40)));
+        setBackground(ThemeManager.getStatusBarBg());
+        setBorder(BorderFactory.createMatteBorder(1, 0, 0, 0, ThemeManager.getStatusBarBorder()));
         setPreferredSize(new Dimension(800, 22));
 
         Font oiaFont = new Font(Font.MONOSPACED, Font.PLAIN, 12);
 
-        connectionStatus = createLabel("Not Connected", oiaFont, OIA_DIM);
-        tlsStatus = createLabel("", oiaFont, OIA_FG);
-        luName = createLabel("", oiaFont, OIA_FG);
-        lockStatus = createLabel("", oiaFont, OIA_ALERT);
-        fieldTypeStatus = createLabel("", oiaFont, OIA_DIM);
-        codePageInfo = createLabel("", oiaFont, OIA_DIM);
-        modelInfo = createLabel("", oiaFont, OIA_DIM);
-        cursorPosition = createLabel("001/001 [0000]", oiaFont, OIA_FG);
+        connectionStatus = createLabel("Not Connected", oiaFont, ThemeManager.getOiaFgDim());
+        tlsStatus = createLabel("", oiaFont, ThemeManager.getOiaFgNormal());
+        luName = createLabel("", oiaFont, ThemeManager.getOiaFgNormal());
+        lockStatus = createLabel("", oiaFont, ThemeManager.getOiaFgAlert());
+        fieldTypeStatus = createLabel("", oiaFont, ThemeManager.getOiaFgDim());
+        codePageInfo = createLabel("", oiaFont, ThemeManager.getOiaFgDim());
+        modelInfo = createLabel("", oiaFont, ThemeManager.getOiaFgDim());
+        cursorPosition = createLabel("001/001 [0000]", oiaFont, ThemeManager.getOiaFgNormal());
 
         add(Box.createHorizontalStrut(6));
         add(connectionStatus);
@@ -82,10 +75,17 @@ public class StatusBar extends JPanel {
         updateStatus();
     }
 
+    public void applyTheme(UITheme theme) {
+        setBackground(ThemeManager.getStatusBarBg(theme));
+        setBorder(BorderFactory.createMatteBorder(1, 0, 0, 0, ThemeManager.getStatusBarBorder(theme)));
+        updateStatus();
+    }
+
     public void updateStatus() {
+        UITheme theme = ThemeManager.getTheme();
         if (client == null) {
             connectionStatus.setText("Not Connected");
-            connectionStatus.setForeground(OIA_DIM);
+            connectionStatus.setForeground(ThemeManager.getOiaFgDim(theme));
             tlsStatus.setText("");
             luName.setText("");
             lockStatus.setText("");
@@ -101,38 +101,38 @@ public class StatusBar extends JPanel {
         switch (state) {
             case NOT_CONNECTED:
                 connectionStatus.setText("Not Connected");
-                connectionStatus.setForeground(OIA_DIM);
+                connectionStatus.setForeground(ThemeManager.getOiaFgDim(theme));
                 break;
             case TCP_PENDING:
             case TELNET_PENDING:
                 connectionStatus.setText("Connecting...");
-                connectionStatus.setForeground(OIA_ALERT);
+                connectionStatus.setForeground(ThemeManager.getOiaFgAlert(theme));
                 break;
             case CONNECTED_3270:
                 connectionStatus.setText("TN3270");
-                connectionStatus.setForeground(OIA_FG);
+                connectionStatus.setForeground(ThemeManager.getOiaFgNormal(theme));
                 break;
             case CONNECTED_TN3270E:
                 connectionStatus.setText("TN3270E");
-                connectionStatus.setForeground(OIA_FG);
+                connectionStatus.setForeground(ThemeManager.getOiaFgNormal(theme));
                 break;
             case CONNECTED_SSCP:
                 connectionStatus.setText("SSCP-LU");
-                connectionStatus.setForeground(OIA_FG);
+                connectionStatus.setForeground(ThemeManager.getOiaFgNormal(theme));
                 break;
             case CONNECTED_NVT:
             case CONNECTED_NVT_CHAR:
             case CONNECTED_E_NVT:
                 connectionStatus.setText("NVT");
-                connectionStatus.setForeground(OIA_FG);
+                connectionStatus.setForeground(ThemeManager.getOiaFgNormal(theme));
                 break;
             case CONNECTED_UNBOUND:
                 connectionStatus.setText("Unbound");
-                connectionStatus.setForeground(OIA_WARN);
+                connectionStatus.setForeground(ThemeManager.getOiaFgWarn(theme));
                 break;
             default:
                 connectionStatus.setText(state.name());
-                connectionStatus.setForeground(OIA_DIM);
+                connectionStatus.setForeground(ThemeManager.getOiaFgDim(theme));
                 break;
         }
 
@@ -144,11 +144,11 @@ public class StatusBar extends JPanel {
             String protocol = session != null ? session.getProtocol() : "TLS";
             if (verified) {
                 tlsStatus.setText("🔒 TLS");
-                tlsStatus.setForeground(OIA_FG);
+                tlsStatus.setForeground(ThemeManager.getOiaFgNormal(theme));
                 tlsStatus.setToolTipText(protocol + " / " + cipher + " (Verified)");
             } else {
                 tlsStatus.setText("🔓 TLS (Unverified)");
-                tlsStatus.setForeground(new Color(255, 180, 80));
+                tlsStatus.setForeground(ThemeManager.getOiaFgWarn(theme));
                 tlsStatus.setToolTipText(protocol + " / " + cipher + " (Verification Bypassed)");
             }
         } else {
@@ -164,6 +164,7 @@ public class StatusBar extends JPanel {
             lu = "LU:" + client.getConfig().getLuName();
         }
         luName.setText(lu);
+        luName.setForeground(ThemeManager.getOiaFgNormal(theme));
 
         // Lock / Inhibit status
         int inhibit = client.getOIA().getInputInhibited();
@@ -191,10 +192,10 @@ public class StatusBar extends JPanel {
                     lockStatus.setText("X LOCKED");
                     break;
             }
-            lockStatus.setForeground(OIA_ALERT);
+            lockStatus.setForeground(ThemeManager.getOiaFgAlert(theme));
         } else if (client.getInputProcessor().isInsertMode()) {
             lockStatus.setText("INSERT");
-            lockStatus.setForeground(OIA_FG);
+            lockStatus.setForeground(ThemeManager.getOiaFgNormal(theme));
         } else {
             lockStatus.setText("");
         }
@@ -203,10 +204,10 @@ public class StatusBar extends JPanel {
         if (state.isFullSession() && client.getScreenBuffer().isFormatted()) {
             if (client.getOIA().isNumeric()) {
                 fieldTypeStatus.setText("NUM");
-                fieldTypeStatus.setForeground(OIA_WARN);
+                fieldTypeStatus.setForeground(ThemeManager.getOiaFgWarn(theme));
             } else {
                 fieldTypeStatus.setText("ALPHA");
-                fieldTypeStatus.setForeground(OIA_DIM);
+                fieldTypeStatus.setForeground(ThemeManager.getOiaFgDim(theme));
             }
         } else {
             fieldTypeStatus.setText("");
@@ -215,6 +216,7 @@ public class StatusBar extends JPanel {
         // Active Code Page
         String cp = client.getCodePage();
         codePageInfo.setText(cp != null ? "CP" + cp : "");
+        codePageInfo.setForeground(ThemeManager.getOiaFgDim(theme));
         codePageInfo.setToolTipText("Active EBCDIC Code Page: CP" + cp);
 
         // Model & Dimensions info
@@ -222,11 +224,13 @@ public class StatusBar extends JPanel {
         int rows = sb.getDisplayRows();
         int cols = sb.getDisplayCols();
         modelInfo.setText(client.getConfig().getModel().name().replace('_', '-') + " [" + rows + "x" + cols + "]");
+        modelInfo.setForeground(ThemeManager.getOiaFgDim(theme));
 
         // Cursor position and buffer address
         int curAddr = sb.getCursorAddress();
         int row = sb.getCursorRow() + 1;
         int col = sb.getCursorCol() + 1;
         cursorPosition.setText(String.format("%03d/%03d [%04d]", row, col, curAddr));
+        cursorPosition.setForeground(ThemeManager.getOiaFgNormal(theme));
     }
 }
diff --git a/j3270/src/main/java/haus/nightmare/j3270/ui/TerminalPanel.java b/j3270/src/main/java/haus/nightmare/j3270/ui/TerminalPanel.java
index 1ffa1fa..0a01b8a 100644
--- a/j3270/src/main/java/haus/nightmare/j3270/ui/TerminalPanel.java
+++ b/j3270/src/main/java/haus/nightmare/j3270/ui/TerminalPanel.java
@@ -434,6 +434,16 @@ public class TerminalPanel extends JPanel implements java.awt.print.Printable {
 
     public void pasteClipboard() {
         if (client == null || !client.getConnectionState().isFullSession()) return;
+        if (client.getConnectionState().isNvt()) {
+            try {
+                String text = (String) Toolkit.getDefaultToolkit().getSystemClipboard()
+                    .getData(DataFlavor.stringFlavor);
+                if (text != null && !text.isEmpty()) {
+                    client.sendNVTString(text);
+                }
+            } catch (Exception ignored) {}
+            return;
+        }
         try {
             String text = (String) Toolkit.getDefaultToolkit().getSystemClipboard()
                 .getData(DataFlavor.stringFlavor);
@@ -481,24 +491,29 @@ public class TerminalPanel extends JPanel implements java.awt.print.Printable {
 
     private void showContextMenu(MouseEvent e) {
         JPopupMenu popup = new JPopupMenu();
+        ThemeManager.stylePopupMenu(popup);
 
         JMenuItem copyItem = new JMenuItem("Copy");
+        ThemeManager.styleMenuItem(copyItem);
         copyItem.setEnabled(hasSelection());
         copyItem.addActionListener(ev -> copySelection());
         popup.add(copyItem);
 
         JMenuItem pasteItem = new JMenuItem("Paste");
+        ThemeManager.styleMenuItem(pasteItem);
         pasteItem.setEnabled(client != null && client.getConnectionState().isFullSession());
         pasteItem.addActionListener(ev -> pasteClipboard());
         popup.add(pasteItem);
 
         JMenuItem selectAllItem = new JMenuItem("Select All");
+        ThemeManager.styleMenuItem(selectAllItem);
         selectAllItem.addActionListener(ev -> selectAll());
         popup.add(selectAllItem);
 
         popup.addSeparator();
 
         JCheckBoxMenuItem blockModeItem = new JCheckBoxMenuItem("Block Select Mode", blockSelectMode);
+        ThemeManager.styleMenuItem(blockModeItem);
         blockModeItem.addActionListener(ev -> {
             blockSelectMode = blockModeItem.isSelected();
             haus.nightmare.j3270.config.Settings.setBlockSelectMode(blockSelectMode);
@@ -693,19 +708,63 @@ public class TerminalPanel extends JPanel implements java.awt.print.Printable {
 
     @Override
     protected void processKeyEvent(KeyEvent e) {
-        if (e.getID() == KeyEvent.KEY_TYPED) {
-            char ch = e.getKeyChar();
-            if (ch >= 0x20 && ch != 0x7F && ch != KeyEvent.CHAR_UNDEFINED
-                    && !e.isControlDown() && !e.isAltDown() && !e.isMetaDown()) {
-                if (client != null) {
-                    ConnectionState state = client.getConnectionState();
-                    if (state == ConnectionState.CONNECTED_NVT || state == ConnectionState.CONNECTED_NVT_CHAR || state == ConnectionState.CONNECTED_E_NVT) {
+        if (client != null) {
+            ConnectionState state = client.getConnectionState();
+            if (state.isNvt()) {
+                if (e.getID() == KeyEvent.KEY_TYPED) {
+                    char ch = e.getKeyChar();
+                    if (ch >= 0x20 && ch != 0x7F && ch != KeyEvent.CHAR_UNDEFINED
+                            && !e.isControlDown() && !e.isAltDown() && !e.isMetaDown()) {
                         try {
                             client.sendNVTChar(ch);
                         } catch (Exception ignored) {}
                         e.consume();
                         return;
-                    } else if (state.isFullSession()) {
+                    } else if (e.isControlDown() && !e.isAltDown() && !e.isMetaDown()) {
+                        if (ch > 0 && ch < 0x20) {
+                            try {
+                                client.sendNVTChar(ch);
+                            } catch (Exception ignored) {}
+                            e.consume();
+                            return;
+                        }
+                    }
+                } else if (e.getID() == KeyEvent.KEY_PRESSED) {
+                    if (e.isControlDown() && !e.isAltDown() && !e.isMetaDown()) {
+                        int code = e.getKeyCode();
+                        if (code >= KeyEvent.VK_A && code <= KeyEvent.VK_Z) {
+                            char ctrlChar = (char) (code - KeyEvent.VK_A + 1);
+                            try {
+                                client.sendNVTChar(ctrlChar);
+                            } catch (Exception ignored) {}
+                            e.consume();
+                            return;
+                        } else if (code == KeyEvent.VK_OPEN_BRACKET) { // Ctrl+[ = ESC
+                            try {
+                                client.sendNVTChar('\u001B');
+                            } catch (Exception ignored) {}
+                            e.consume();
+                            return;
+                        } else if (code == KeyEvent.VK_BACK_SLASH) { // Ctrl+\ = FS
+                            try {
+                                client.sendNVTChar('\u001C');
+                            } catch (Exception ignored) {}
+                            e.consume();
+                            return;
+                        } else if (code == KeyEvent.VK_CLOSE_BRACKET) { // Ctrl+] = GS
+                            try {
+                                client.sendNVTChar('\u001D');
+                            } catch (Exception ignored) {}
+                            e.consume();
+                            return;
+                        }
+                    }
+                }
+            } else if (e.getID() == KeyEvent.KEY_TYPED) {
+                char ch = e.getKeyChar();
+                if (ch >= 0x20 && ch != 0x7F && ch != KeyEvent.CHAR_UNDEFINED
+                        && !e.isControlDown() && !e.isAltDown() && !e.isMetaDown()) {
+                    if (state.isFullSession()) {
                         client.typeCharacter(ch);
                         refreshScreen();
                         e.consume();
@@ -731,7 +790,7 @@ public class TerminalPanel extends JPanel implements java.awt.print.Printable {
     private void handleEnter() {
         if (client != null) {
             ConnectionState state = client.getConnectionState();
-            if (state == ConnectionState.CONNECTED_NVT || state == ConnectionState.CONNECTED_NVT_CHAR || state == ConnectionState.CONNECTED_E_NVT) {
+            if (state.isNvt()) {
                 try {
                     client.sendNVTString("\r\n");
                 } catch (Exception ignored) {}
@@ -744,6 +803,12 @@ public class TerminalPanel extends JPanel implements java.awt.print.Printable {
 
     private void handleReset() {
         if (client != null) {
+            if (client.getConnectionState().isNvt()) {
+                try {
+                    client.sendNVTChar('\u001B');
+                } catch (Exception ignored) {}
+                return;
+            }
             clearSearchHighlight();
             clearSelection();
             client.reset();
@@ -753,6 +818,16 @@ public class TerminalPanel extends JPanel implements java.awt.print.Printable {
 
     private void handleTab(boolean shift) {
         if (client != null && client.getConnectionState().isFullSession()) {
+            if (client.getConnectionState().isNvt()) {
+                try {
+                    if (shift) {
+                        client.sendNVTString("\u001B[Z");
+                    } else {
+                        client.sendNVTChar('\t');
+                    }
+                } catch (Exception ignored) {}
+                return;
+            }
             if (shift) client.backTab();
             else client.tab();
             refreshScreen();
@@ -761,6 +836,18 @@ public class TerminalPanel extends JPanel implements java.awt.print.Printable {
 
     private void handleCursor(String dir) {
         if (client != null && client.getConnectionState().isFullSession()) {
+            if (client.getConnectionState().isNvt()) {
+                try {
+                    switch (dir) {
+                        case "up": client.sendNVTString("\u001B[A"); break;
+                        case "down": client.sendNVTString("\u001B[B"); break;
+                        case "left": client.sendNVTString("\u001B[D"); break;
+                        case "right": client.sendNVTString("\u001B[C"); break;
+                        case "home": client.sendNVTString("\u001B[H"); break;
+                    }
+                } catch (Exception ignored) {}
+                return;
+            }
             switch (dir) {
                 case "up": client.cursorUp(); break;
                 case "down": client.cursorDown(); break;
@@ -774,11 +861,35 @@ public class TerminalPanel extends JPanel implements java.awt.print.Printable {
 
     private void handlePF(int n) {
         if (client != null && client.getConnectionState().isFullSession()) {
+            if (client.getConnectionState().isNvt()) {
+                try {
+                    client.sendNVTString(getNvtFunctionKeySequence(n));
+                } catch (Exception ignored) {}
+                return;
+            }
             client.sendPF(n);
             refreshScreen();
         }
     }
 
+    private String getNvtFunctionKeySequence(int n) {
+        switch (n) {
+            case 1: return "\u001BOP";
+            case 2: return "\u001BOQ";
+            case 3: return "\u001BOR";
+            case 4: return "\u001BOS";
+            case 5: return "\u001B[15~";
+            case 6: return "\u001B[17~";
+            case 7: return "\u001B[18~";
+            case 8: return "\u001B[19~";
+            case 9: return "\u001B[20~";
+            case 10: return "\u001B[21~";
+            case 11: return "\u001B[23~";
+            case 12: return "\u001B[24~";
+            default: return "";
+        }
+    }
+
     private void handlePA(int n) {
         if (client != null && client.getConnectionState().isFullSession()) {
             client.sendPA(n);
@@ -788,6 +899,12 @@ public class TerminalPanel extends JPanel implements java.awt.print.Printable {
 
     private void handleEraseEOF() {
         if (client != null && client.getConnectionState().isFullSession()) {
+            if (client.getConnectionState().isNvt()) {
+                try {
+                    client.sendNVTString("\u001B[F");
+                } catch (Exception ignored) {}
+                return;
+            }
             client.getInputProcessor().eraseEof();
             refreshScreen();
         }
@@ -795,6 +912,12 @@ public class TerminalPanel extends JPanel implements java.awt.print.Printable {
 
     private void handleDelete() {
         if (client != null && client.getConnectionState().isFullSession()) {
+            if (client.getConnectionState().isNvt()) {
+                try {
+                    client.sendNVTString("\u001B[3~");
+                } catch (Exception ignored) {}
+                return;
+            }
             client.getInputProcessor().deleteChar();
             refreshScreen();
         }
@@ -803,7 +926,7 @@ public class TerminalPanel extends JPanel implements java.awt.print.Printable {
     private void handleBackspace() {
         if (client != null) {
             ConnectionState state = client.getConnectionState();
-            if (state == ConnectionState.CONNECTED_NVT || state == ConnectionState.CONNECTED_NVT_CHAR || state == ConnectionState.CONNECTED_E_NVT) {
+            if (state.isNvt()) {
                 try {
                     client.sendNVTChar('\b');
                 } catch (Exception ignored) {}
@@ -824,6 +947,12 @@ public class TerminalPanel extends JPanel implements java.awt.print.Printable {
 
     private void handleClear() {
         if (client != null && client.getConnectionState().isFullSession()) {
+            if (client.getConnectionState().isNvt()) {
+                try {
+                    client.sendNVTChar('\u000C');
+                } catch (Exception ignored) {}
+                return;
+            }
             client.sendClear();
             refreshScreen();
         }
diff --git a/j3270/src/main/java/haus/nightmare/j3270/ui/ThemeManager.java b/j3270/src/main/java/haus/nightmare/j3270/ui/ThemeManager.java
new file mode 100644
index 0000000..9bcad98
--- /dev/null
+++ b/j3270/src/main/java/haus/nightmare/j3270/ui/ThemeManager.java
@@ -0,0 +1,955 @@
+package haus.nightmare.j3270.ui;
+
+import javax.swing.*;
+import javax.swing.border.Border;
+import javax.swing.border.CompoundBorder;
+import javax.swing.border.EmptyBorder;
+import javax.swing.border.LineBorder;
+import javax.swing.border.TitledBorder;
+import javax.swing.plaf.basic.BasicButtonUI;
+import javax.swing.plaf.basic.BasicMenuBarUI;
+import javax.swing.plaf.basic.BasicMenuItemUI;
+import javax.swing.plaf.basic.BasicMenuUI;
+import javax.swing.plaf.basic.BasicPopupMenuUI;
+import javax.swing.plaf.basic.BasicTabbedPaneUI;
+import javax.swing.table.DefaultTableCellRenderer;
+import javax.swing.table.JTableHeader;
+import java.awt.*;
+import java.awt.event.MouseAdapter;
+import java.awt.event.MouseEvent;
+import java.util.ArrayList;
+import java.util.List;
+import java.util.function.Consumer;
+
+/**
+ * Centralized theme manager for j3270 Java desktop UI.
+ * Provides high-contrast, platform-independent Light and Dark theme palettes,
+ * custom Swing UI delegates, and recursive styling helpers for all dialogs and menus.
+ */
+public final class ThemeManager {
+
+    private static UITheme currentTheme = UITheme.DARK;
+    private static final List<Consumer<UITheme>> themeChangeListeners = new ArrayList<>();
+
+    private ThemeManager() {}
+
+    public static UITheme getTheme() {
+        return currentTheme;
+    }
+
+    public static boolean isDark() {
+        return currentTheme == UITheme.DARK;
+    }
+
+    public static boolean isLight() {
+        return currentTheme == UITheme.LIGHT;
+    }
+
+    public static void setTheme(UITheme theme) {
+        if (theme == null) theme = UITheme.DARK;
+        if (currentTheme != theme) {
+            currentTheme = theme;
+            applyUIManagerDefaults(theme);
+            for (Consumer<UITheme> listener : new ArrayList<>(themeChangeListeners)) {
+                try {
+                    listener.accept(theme);
+                } catch (Exception ignored) {}
+            }
+        }
+    }
+
+    public static void addThemeChangeListener(Consumer<UITheme> listener) {
+        if (listener != null && !themeChangeListeners.contains(listener)) {
+            themeChangeListeners.add(listener);
+        }
+    }
+
+    public static void removeThemeChangeListener(Consumer<UITheme> listener) {
+        themeChangeListeners.remove(listener);
+    }
+
+    // =========================================================================
+    // Color Palette Tokens
+    // =========================================================================
+
+    public static Color getBgMain() { return getBgMain(currentTheme); }
+    public static Color getBgMain(UITheme t) {
+        return t == UITheme.DARK ? new Color(28, 28, 28) : new Color(242, 242, 244);
+    }
+
+    public static Color getBgPanel() { return getBgPanel(currentTheme); }
+    public static Color getBgPanel(UITheme t) {
+        return t == UITheme.DARK ? new Color(36, 36, 36) : new Color(250, 250, 252);
+    }
+
+    public static Color getBgComponent() { return getBgComponent(currentTheme); }
+    public static Color getBgComponent(UITheme t) {
+        return t == UITheme.DARK ? new Color(46, 46, 46) : Color.WHITE;
+    }
+
+    public static Color getBgComponentLighter() { return getBgComponentLighter(currentTheme); }
+    public static Color getBgComponentLighter(UITheme t) {
+        return t == UITheme.DARK ? new Color(56, 56, 56) : new Color(236, 236, 238);
+    }
+
+    public static Color getFgMain() { return getFgMain(currentTheme); }
+    public static Color getFgMain(UITheme t) {
+        return t == UITheme.DARK ? new Color(238, 238, 238) : new Color(24, 24, 24);
+    }
+
+    public static Color getFgMuted() { return getFgMuted(currentTheme); }
+    public static Color getFgMuted(UITheme t) {
+        return t == UITheme.DARK ? new Color(175, 175, 175) : new Color(90, 90, 90);
+    }
+
+    public static Color getFgDisabled() { return getFgDisabled(currentTheme); }
+    public static Color getFgDisabled(UITheme t) {
+        return t == UITheme.DARK ? new Color(110, 110, 110) : new Color(160, 160, 160);
+    }
+
+    public static Color getBorder() { return getBorder(currentTheme); }
+    public static Color getBorder(UITheme t) {
+        return t == UITheme.DARK ? new Color(65, 65, 65) : new Color(205, 205, 205);
+    }
+    public static Color getBorderColor() { return getBorder(currentTheme); }
+    public static Color getBorderColor(UITheme t) { return getBorder(t); }
+
+    public static Color getBorderFocused() { return getBorderFocused(currentTheme); }
+    public static Color getBorderFocused(UITheme t) {
+        return t == UITheme.DARK ? new Color(80, 140, 230) : new Color(50, 115, 220);
+    }
+
+    public static Color getSelectionBg() { return getSelectionBg(currentTheme); }
+    public static Color getSelectionBg(UITheme t) {
+        return t == UITheme.DARK ? new Color(55, 105, 180) : new Color(60, 125, 215);
+    }
+
+    public static Color getSelectionFg() { return getSelectionFg(currentTheme); }
+    public static Color getSelectionFg(UITheme t) {
+        return Color.WHITE;
+    }
+
+    public static Color getMenuBarBg() { return getMenuBarBg(currentTheme); }
+    public static Color getMenuBarBg(UITheme t) {
+        return t == UITheme.DARK ? new Color(26, 26, 26) : new Color(240, 240, 242);
+    }
+
+    public static Color getMenuBarFg() { return getMenuBarFg(currentTheme); }
+    public static Color getMenuBarFg(UITheme t) {
+        return t == UITheme.DARK ? new Color(235, 235, 235) : new Color(25, 25, 25);
+    }
+
+    public static Color getMenuPopupBg() { return getMenuPopupBg(currentTheme); }
+    public static Color getMenuPopupBg(UITheme t) {
+        return t == UITheme.DARK ? new Color(38, 38, 38) : Color.WHITE;
+    }
+
+    public static Color getMenuItemFg() { return getMenuItemFg(currentTheme); }
+    public static Color getMenuItemFg(UITheme t) {
+        return t == UITheme.DARK ? new Color(230, 230, 230) : new Color(30, 30, 30);
+    }
+
+    public static Color getMenuItemHoverBg() { return getMenuItemHoverBg(currentTheme); }
+    public static Color getMenuItemHoverBg(UITheme t) {
+        return t == UITheme.DARK ? new Color(55, 95, 160) : new Color(220, 232, 250);
+    }
+
+    public static Color getMenuItemHoverFg() { return getMenuItemHoverFg(currentTheme); }
+    public static Color getMenuItemHoverFg(UITheme t) {
+        return t == UITheme.DARK ? Color.WHITE : new Color(15, 15, 15);
+    }
+
+    public static Color getTabBg() { return getTabBg(currentTheme); }
+    public static Color getTabBg(UITheme t) {
+        return t == UITheme.DARK ? new Color(34, 34, 34) : new Color(230, 230, 232);
+    }
+
+    public static Color getTabFg() { return getTabFg(currentTheme); }
+    public static Color getTabFg(UITheme t) {
+        return t == UITheme.DARK ? new Color(185, 185, 185) : new Color(75, 75, 75);
+    }
+
+    public static Color getTabSelectedBg() { return getTabSelectedBg(currentTheme); }
+    public static Color getTabSelectedBg(UITheme t) {
+        return t == UITheme.DARK ? new Color(50, 50, 50) : Color.WHITE;
+    }
+
+    public static Color getTabSelectedFg() { return getTabSelectedFg(currentTheme); }
+    public static Color getTabSelectedFg(UITheme t) {
+        return t == UITheme.DARK ? Color.WHITE : new Color(20, 20, 20);
+    }
+
+    public static Color getTableHeaderBg() { return getTableHeaderBg(currentTheme); }
+    public static Color getTableHeaderBg(UITheme t) {
+        return t == UITheme.DARK ? new Color(46, 46, 46) : new Color(232, 232, 236);
+    }
+
+    public static Color getTableHeaderFg() { return getTableHeaderFg(currentTheme); }
+    public static Color getTableHeaderFg(UITheme t) {
+        return t == UITheme.DARK ? new Color(235, 235, 235) : new Color(30, 30, 30);
+    }
+
+    public static Color getTableRowEven() { return getTableRowEven(currentTheme); }
+    public static Color getTableRowEven(UITheme t) {
+        return t == UITheme.DARK ? new Color(38, 38, 38) : Color.WHITE;
+    }
+
+    public static Color getTableRowOdd() { return getTableRowOdd(currentTheme); }
+    public static Color getTableRowOdd(UITheme t) {
+        return t == UITheme.DARK ? new Color(33, 33, 33) : new Color(246, 247, 249);
+    }
+
+    public static Color getTableGrid() { return getTableGrid(currentTheme); }
+    public static Color getTableGrid(UITheme t) {
+        return t == UITheme.DARK ? new Color(55, 55, 55) : new Color(225, 225, 225);
+    }
+
+    public static Color getCodeAreaBg() { return getCodeAreaBg(currentTheme); }
+    public static Color getCodeAreaBg(UITheme t) {
+        return t == UITheme.DARK ? new Color(22, 22, 22) : new Color(252, 252, 252);
+    }
+
+    public static Color getCodeAreaFg() { return getCodeAreaFg(currentTheme); }
+    public static Color getCodeAreaFg(UITheme t) {
+        return t == UITheme.DARK ? new Color(80, 230, 80) : new Color(0, 120, 0);
+    }
+
+    public static Color getStatusBarBg() { return getStatusBarBg(currentTheme); }
+    public static Color getStatusBarBg(UITheme t) {
+        return t == UITheme.DARK ? new Color(20, 20, 20) : new Color(235, 235, 238);
+    }
+
+    public static Color getStatusBarBorder() { return getStatusBarBorder(currentTheme); }
+    public static Color getStatusBarBorder(UITheme t) {
+        return t == UITheme.DARK ? new Color(42, 42, 42) : new Color(210, 210, 215);
+    }
+
+    public static Color getOiaFgNormal() { return getOiaFgNormal(currentTheme); }
+    public static Color getOiaFgNormal(UITheme t) {
+        return t == UITheme.DARK ? new Color(50, 205, 50) : new Color(0, 130, 0);
+    }
+
+    public static Color getOiaFgDim() { return getOiaFgDim(currentTheme); }
+    public static Color getOiaFgDim(UITheme t) {
+        return t == UITheme.DARK ? new Color(110, 110, 110) : new Color(90, 90, 90);
+    }
+
+    public static Color getOiaFgAlert() { return getOiaFgAlert(currentTheme); }
+    public static Color getOiaFgAlert(UITheme t) {
+        return t == UITheme.DARK ? new Color(255, 80, 80) : new Color(190, 20, 20);
+    }
+
+    public static Color getOiaFgWarn() { return getOiaFgWarn(currentTheme); }
+    public static Color getOiaFgWarn(UITheme t) {
+        return t == UITheme.DARK ? new Color(255, 190, 70) : new Color(180, 100, 0);
+    }
+
+    // =========================================================================
+    // Button Variants & Color helpers
+    // =========================================================================
+
+    public enum ButtonVariant {
+        DEFAULT,
+        PRIMARY,
+        CANCEL,
+        DANGER,
+        ACCENT
+    }
+
+    public static Color getButtonBg(ButtonVariant variant) {
+        return getButtonBg(variant, currentTheme, false, false);
+    }
+
+    public static Color getButtonBg(ButtonVariant variant, UITheme t) {
+        return getButtonBg(variant, t, false, false);
+    }
+
+    public static Color getButtonBg(ButtonVariant variant, UITheme t, boolean hover, boolean pressed) {
+        switch (variant) {
+            case PRIMARY:
+                if (pressed) return new Color(25, 105, 35);
+                if (hover) return new Color(38, 145, 48);
+                return new Color(32, 128, 42);
+
+            case DANGER:
+                if (pressed) return new Color(125, 30, 30);
+                if (hover) return new Color(165, 45, 45);
+                return new Color(145, 38, 38);
+
+            case ACCENT:
+                if (pressed) return new Color(35, 80, 145);
+                if (hover) return new Color(55, 115, 195);
+                return new Color(45, 100, 175);
+
+            case CANCEL:
+            case DEFAULT:
+            default:
+                if (t == UITheme.DARK) {
+                    if (pressed) return new Color(42, 42, 42);
+                    if (hover) return new Color(68, 68, 68);
+                    return new Color(56, 56, 56);
+                } else {
+                    if (pressed) return new Color(210, 210, 212);
+                    if (hover) return new Color(228, 228, 232);
+                    return new Color(238, 238, 240);
+                }
+        }
+    }
+
+    public static Color getButtonFg(ButtonVariant variant, UITheme t) {
+        switch (variant) {
+            case PRIMARY:
+            case DANGER:
+            case ACCENT:
+                return Color.WHITE;
+            case CANCEL:
+            case DEFAULT:
+            default:
+                return t == UITheme.DARK ? new Color(235, 235, 235) : new Color(30, 30, 30);
+        }
+    }
+
+    // =========================================================================
+    // UIManager Defaults Configuration
+    // =========================================================================
+
+    public static void applyUIManagerDefaults(UITheme theme) {
+        Color bgMain = getBgMain(theme);
+        Color bgPanel = getBgPanel(theme);
+        Color bgComp = getBgComponent(theme);
+        Color fgMain = getFgMain(theme);
+        Color fgMuted = getFgMuted(theme);
+        Color border = getBorder(theme);
+        Color selBg = getSelectionBg(theme);
+        Color selFg = getSelectionFg(theme);
+
+        UIManager.put("Panel.background", bgPanel);
+        UIManager.put("Panel.foreground", fgMain);
+        UIManager.put("Label.foreground", fgMain);
+
+        UIManager.put("TextField.background", bgComp);
+        UIManager.put("TextField.foreground", fgMain);
+        UIManager.put("TextField.caretForeground", fgMain);
+        UIManager.put("TextField.selectionBackground", selBg);
+        UIManager.put("TextField.selectionForeground", selFg);
+
+        UIManager.put("TextArea.background", bgComp);
+        UIManager.put("TextArea.foreground", fgMain);
+        UIManager.put("TextArea.caretForeground", fgMain);
+        UIManager.put("TextArea.selectionBackground", selBg);
+        UIManager.put("TextArea.selectionForeground", selFg);
+
+        UIManager.put("Button.background", getBgComponentLighter(theme));
+        UIManager.put("Button.foreground", fgMain);
+        UIManager.put("Button.select", selBg);
+
+        UIManager.put("ComboBox.background", bgComp);
+        UIManager.put("ComboBox.foreground", fgMain);
+        UIManager.put("ComboBox.selectionBackground", selBg);
+        UIManager.put("ComboBox.selectionForeground", selFg);
+
+        UIManager.put("Table.background", bgComp);
+        UIManager.put("Table.foreground", fgMain);
+        UIManager.put("Table.selectionBackground", selBg);
+        UIManager.put("Table.selectionForeground", selFg);
+        UIManager.put("Table.gridColor", getTableGrid(theme));
+
+        UIManager.put("TableHeader.background", getTableHeaderBg(theme));
+        UIManager.put("TableHeader.foreground", getTableHeaderFg(theme));
+
+        UIManager.put("ScrollPane.background", bgPanel);
+        UIManager.put("Viewport.background", bgComp);
+
+        UIManager.put("MenuBar.background", getMenuBarBg(theme));
+        UIManager.put("MenuBar.foreground", getMenuBarFg(theme));
+        UIManager.put("Menu.background", getMenuBarBg(theme));
+        UIManager.put("Menu.foreground", getMenuBarFg(theme));
+        UIManager.put("Menu.selectionBackground", selBg);
+        UIManager.put("Menu.selectionForeground", selFg);
+
+        UIManager.put("PopupMenu.background", getMenuPopupBg(theme));
+        UIManager.put("PopupMenu.foreground", getMenuItemFg(theme));
+
+        UIManager.put("MenuItem.background", getMenuPopupBg(theme));
+        UIManager.put("MenuItem.foreground", getMenuItemFg(theme));
+        UIManager.put("MenuItem.selectionBackground", selBg);
+        UIManager.put("MenuItem.selectionForeground", selFg);
+
+        UIManager.put("CheckBoxMenuItem.background", getMenuPopupBg(theme));
+        UIManager.put("CheckBoxMenuItem.foreground", getMenuItemFg(theme));
+        UIManager.put("CheckBoxMenuItem.selectionBackground", selBg);
+        UIManager.put("CheckBoxMenuItem.selectionForeground", selFg);
+
+        UIManager.put("RadioButtonMenuItem.background", getMenuPopupBg(theme));
+        UIManager.put("RadioButtonMenuItem.foreground", getMenuItemFg(theme));
+        UIManager.put("RadioButtonMenuItem.selectionBackground", selBg);
+        UIManager.put("RadioButtonMenuItem.selectionForeground", selFg);
+
+        UIManager.put("Separator.background", border);
+        UIManager.put("Separator.foreground", border);
+
+        UIManager.put("TabbedPane.background", getTabBg(theme));
+        UIManager.put("TabbedPane.foreground", getTabFg(theme));
+        UIManager.put("TabbedPane.selected", getTabSelectedBg(theme));
+        UIManager.put("TabbedPane.selectHighlight", getTabSelectedBg(theme));
+
+        UIManager.put("CheckBox.background", bgPanel);
+        UIManager.put("CheckBox.foreground", fgMain);
+        UIManager.put("RadioButton.background", bgPanel);
+        UIManager.put("RadioButton.foreground", fgMain);
+
+        UIManager.put("TitledBorder.titleColor", fgMain);
+        UIManager.put("OptionPane.background", bgPanel);
+        UIManager.put("OptionPane.messageForeground", fgMain);
+    }
+
+    // =========================================================================
+    // Component Styling & Custom UI Delegates
+    // =========================================================================
+
+    /**
+     * Styles a button with custom rendering, ensuring consistent high contrast
+     * and proper background color across Windows, macOS, and Linux.
+     */
+    public static JButton styleButton(JButton button, ButtonVariant variant) {
+        if (button == null) return null;
+        button.setUI(new StyledButtonUI(variant));
+        button.setFocusPainted(false);
+        button.setOpaque(false);
+        button.setContentAreaFilled(false);
+        button.setBorder(BorderFactory.createEmptyBorder(6, 14, 6, 14));
+        button.setCursor(Cursor.getPredefinedCursor(Cursor.HAND_CURSOR));
+        return button;
+    }
+
+    public static JButton createStyledButton(String text, ButtonVariant variant, Runnable action) {
+        JButton btn = new JButton(text);
+        styleButton(btn, variant);
+        if (action != null) {
+            btn.addActionListener(e -> action.run());
+        }
+        return btn;
+    }
+
+    public static JTextField styleTextField(JTextField field) {
+        if (field == null) return null;
+        field.setBackground(getBgComponent());
+        field.setForeground(getFgMain());
+        field.setCaretColor(getFgMain());
+        field.setSelectionColor(getSelectionBg());
+        field.setSelectedTextColor(getSelectionFg());
+        field.setBorder(BorderFactory.createCompoundBorder(
+                new LineBorder(getBorder(), 1, true),
+                new EmptyBorder(4, 8, 4, 8)));
+        return field;
+    }
+
+    public static JTextArea styleTextArea(JTextArea area) {
+        if (area == null) return null;
+        area.setBackground(getCodeAreaBg());
+        area.setForeground(getCodeAreaFg());
+        area.setCaretColor(getFgMain());
+        area.setSelectionColor(getSelectionBg());
+        area.setSelectedTextColor(getSelectionFg());
+        return area;
+    }
+
+    public static JComboBox<?> styleComboBox(JComboBox<?> box) {
+        if (box == null) return null;
+        box.setBackground(getBgComponent());
+        box.setForeground(getFgMain());
+        box.setRenderer(new DefaultListCellRenderer() {
+            @Override
+            public Component getListCellRendererComponent(JList<?> list, Object value, int index, boolean isSelected, boolean cellHasFocus) {
+                super.getListCellRendererComponent(list, value, index, isSelected, cellHasFocus);
+                setBorder(new EmptyBorder(4, 8, 4, 8));
+                if (isSelected) {
+                    setBackground(getSelectionBg());
+                    setForeground(getSelectionFg());
+                } else {
+                    setBackground(getBgComponent());
+                    setForeground(getFgMain());
+                }
+                return this;
+            }
+        });
+        return box;
+    }
+
+    public static JTable styleTable(JTable table) {
+        if (table == null) return null;
+        table.setBackground(getBgComponent());
+        table.setForeground(getFgMain());
+        table.setSelectionBackground(getSelectionBg());
+        table.setSelectionForeground(getSelectionFg());
+        table.setGridColor(getTableGrid());
+        table.setRowHeight(24);
+
+        table.setDefaultRenderer(Object.class, new DefaultTableCellRenderer() {
+            @Override
+            public Component getTableCellRendererComponent(JTable tbl, Object val, boolean isSel, boolean hasFocus, int row, int col) {
+                super.getTableCellRendererComponent(tbl, val, isSel, hasFocus, row, col);
+                setBorder(new EmptyBorder(2, 6, 2, 6));
+                if (isSel) {
+                    setBackground(getSelectionBg());
+                    setForeground(getSelectionFg());
+                } else {
+                    setBackground(row % 2 == 0 ? getTableRowEven() : getTableRowOdd());
+                    setForeground(getFgMain());
+                }
+                return this;
+            }
+        });
+
+        JTableHeader header = table.getTableHeader();
+        if (header != null) {
+            header.setBackground(getTableHeaderBg());
+            header.setForeground(getTableHeaderFg());
+            header.setFont(header.getFont().deriveFont(Font.BOLD));
+            header.setDefaultRenderer(new DefaultTableCellRenderer() {
+                @Override
+                public Component getTableCellRendererComponent(JTable tbl, Object val, boolean isSel, boolean hasFocus, int row, int col) {
+                    super.getTableCellRendererComponent(tbl, val, isSel, hasFocus, row, col);
+                    setBackground(getTableHeaderBg());
+                    setForeground(getTableHeaderFg());
+                    setFont(getFont().deriveFont(Font.BOLD));
+                    setBorder(BorderFactory.createCompoundBorder(
+                            BorderFactory.createMatteBorder(0, 0, 1, 1, getBorderColor()),
+                            new EmptyBorder(4, 6, 4, 6)));
+                    return this;
+                }
+            });
+        }
+        return table;
+    }
+
+    public static JTabbedPane styleTabbedPane(JTabbedPane tp) {
+        if (tp == null) return null;
+        tp.setUI(new StyledTabbedPaneUI());
+        tp.setBackground(getBgMain());
+        tp.setForeground(getFgMain());
+        return tp;
+    }
+
+    public static JMenuBar styleMenuBar(JMenuBar bar) {
+        if (bar == null) return null;
+        bar.setUI(new StyledMenuBarUI());
+        bar.setBackground(getMenuBarBg());
+        bar.setBorder(BorderFactory.createMatteBorder(0, 0, 1, 0, getBorder()));
+        return bar;
+    }
+
+    public static JMenu styleMenu(JMenu menu) {
+        if (menu == null) return null;
+        menu.setUI(new StyledMenuUI());
+        menu.setForeground(getMenuBarFg());
+        menu.setBackground(getMenuBarBg());
+        menu.setOpaque(false);
+        return menu;
+    }
+
+    public static JMenuItem styleMenuItem(JMenuItem item) {
+        if (item == null) return null;
+        item.setUI(new StyledMenuItemUI());
+        item.setBackground(getMenuPopupBg());
+        item.setForeground(getMenuItemFg());
+        return item;
+    }
+
+    public static JPopupMenu stylePopupMenu(JPopupMenu popup) {
+        if (popup == null) return null;
+        popup.setUI(new StyledPopupMenuUI());
+        popup.setBackground(getMenuPopupBg());
+        popup.setBorder(BorderFactory.createCompoundBorder(
+                new LineBorder(getBorder(), 1),
+                new EmptyBorder(4, 0, 4, 0)));
+        return popup;
+    }
+
+    public static JScrollPane styleScrollPane(JScrollPane sp) {
+        if (sp == null) return null;
+        sp.setBackground(getBgPanel());
+        if (sp.getViewport() != null) {
+            sp.getViewport().setBackground(getBgComponent());
+        }
+        sp.setBorder(new LineBorder(getBorder(), 1));
+        return sp;
+    }
+
+    public static JSpinner styleSpinner(JSpinner sp) {
+        if (sp == null) return null;
+        sp.setBackground(getBgComponent());
+        sp.setForeground(getFgMain());
+        sp.setBorder(new LineBorder(getBorder(), 1));
+        JComponent editor = sp.getEditor();
+        if (editor instanceof JSpinner.DefaultEditor) {
+            JTextField tf = ((JSpinner.DefaultEditor) editor).getTextField();
+            tf.setBackground(getBgComponent());
+            tf.setForeground(getFgMain());
+            tf.setCaretColor(getFgMain());
+            tf.setBorder(new EmptyBorder(2, 4, 2, 4));
+        }
+        return sp;
+    }
+
+    public static JCheckBox styleCheckBox(JCheckBox cb) {
+        if (cb == null) return null;
+        cb.setOpaque(false);
+        cb.setForeground(getFgMain());
+        cb.setFocusPainted(false);
+        return cb;
+    }
+
+    public static JRadioButton styleRadioButton(JRadioButton rb) {
+        if (rb == null) return null;
+        rb.setOpaque(false);
+        rb.setForeground(getFgMain());
+        rb.setFocusPainted(false);
+        return rb;
+    }
+
+    public static Border createTitledBorder(String title) {
+        return BorderFactory.createTitledBorder(
+                new LineBorder(getBorder(), 1),
+                title,
+                TitledBorder.DEFAULT_JUSTIFICATION,
+                TitledBorder.DEFAULT_POSITION,
+                new Font(Font.SANS_SERIF, Font.BOLD, 12),
+                getFgMain());
+    }
+
+    // =========================================================================
+    // Recursive Component Styling
+    // =========================================================================
+
+    public static void applyTheme(Component comp) {
+        applyTheme(comp, currentTheme);
+    }
+
+    public static void applyTheme(Component comp, UITheme theme) {
+        if (comp == null) return;
+
+        // Skip swatch preview panels whose background is the user-configured color
+        if ("colorSwatch".equals(comp.getName())) {
+            return;
+        }
+
+        if (comp instanceof JMenuBar) {
+            styleMenuBar((JMenuBar) comp);
+            for (int i = 0; i < ((JMenuBar) comp).getMenuCount(); i++) {
+                applyTheme(((JMenuBar) comp).getMenu(i), theme);
+            }
+            return;
+        }
+
+        if (comp instanceof JMenu) {
+            styleMenu((JMenu) comp);
+            JMenu menu = (JMenu) comp;
+            for (int i = 0; i < menu.getItemCount(); i++) {
+                JMenuItem item = menu.getItem(i);
+                if (item != null) applyTheme(item, theme);
+            }
+            return;
+        }
+
+        if (comp instanceof JMenuItem) {
+            styleMenuItem((JMenuItem) comp);
+            return;
+        }
+
+        if (comp instanceof JPopupMenu) {
+            stylePopupMenu((JPopupMenu) comp);
+            for (Component child : ((JPopupMenu) comp).getComponents()) {
+                applyTheme(child, theme);
+            }
+            return;
+        }
+
+        if (comp instanceof JTabbedPane) {
+            styleTabbedPane((JTabbedPane) comp);
+            JTabbedPane tp = (JTabbedPane) comp;
+            for (int i = 0; i < tp.getTabCount(); i++) {
+                applyTheme(tp.getComponentAt(i), theme);
+            }
+            return;
+        }
+
+        if (comp instanceof JTable) {
+            styleTable((JTable) comp);
+            return;
+        }
+
+        if (comp instanceof JScrollPane) {
+            styleScrollPane((JScrollPane) comp);
+            JScrollPane sp = (JScrollPane) comp;
+            if (sp.getViewport() != null) {
+                applyTheme(sp.getViewport().getView(), theme);
+            }
+            return;
+        }
+
+        if (comp instanceof JButton) {
+            JButton btn = (JButton) comp;
+            if (!(btn.getUI() instanceof StyledButtonUI)) {
+                styleButton(btn, ButtonVariant.DEFAULT);
+            }
+            return;
+        }
+
+        if (comp instanceof JComboBox) {
+            styleComboBox((JComboBox<?>) comp);
+            return;
+        }
+
+        if (comp instanceof JSpinner) {
+            styleSpinner((JSpinner) comp);
+            return;
+        }
+
+        if (comp instanceof JTextArea) {
+            styleTextArea((JTextArea) comp);
+            return;
+        }
+
+        if (comp instanceof JTextField) {
+            styleTextField((JTextField) comp);
+            return;
+        }
+
+        if (comp instanceof JCheckBox) {
+            styleCheckBox((JCheckBox) comp);
+            return;
+        }
+
+        if (comp instanceof JRadioButton) {
+            styleRadioButton((JRadioButton) comp);
+            return;
+        }
+
+        if (comp instanceof JLabel) {
+            comp.setForeground(getFgMain(theme));
+            return;
+        }
+
+        if (comp instanceof JPanel) {
+            JPanel panel = (JPanel) comp;
+            if (panel.isOpaque()) {
+                panel.setBackground(getBgPanel(theme));
+            }
+            panel.setForeground(getFgMain(theme));
+            Border b = panel.getBorder();
+            if (b instanceof TitledBorder) {
+                TitledBorder tb = (TitledBorder) b;
+                tb.setTitleColor(getFgMain(theme));
+                tb.setBorder(new LineBorder(getBorder(theme), 1));
+            }
+        } else if (comp instanceof Container) {
+            comp.setBackground(getBgMain(theme));
+            comp.setForeground(getFgMain(theme));
+        }
+
+        if (comp instanceof Container) {
+            for (Component child : ((Container) comp).getComponents()) {
+                applyTheme(child, theme);
+            }
+        }
+    }
+
+    public static void applyThemeToWindow(Window window) {
+        if (window == null) return;
+        window.setBackground(getBgMain());
+        if (window instanceof RootPaneContainer) {
+            RootPaneContainer rpc = (RootPaneContainer) window;
+            if (rpc.getContentPane() != null) {
+                rpc.getContentPane().setBackground(getBgMain());
+                applyTheme(rpc.getContentPane());
+            }
+            if (rpc.getRootPane() != null && rpc.getRootPane().getJMenuBar() != null) {
+                applyTheme(rpc.getRootPane().getJMenuBar());
+            }
+        }
+        window.repaint();
+    }
+
+    // =========================================================================
+    // Custom UI Implementations
+    // =========================================================================
+
+    public static class StyledButtonUI extends BasicButtonUI {
+        private final ButtonVariant variant;
+        private boolean hover = false;
+
+        public StyledButtonUI(ButtonVariant variant) {
+            this.variant = variant != null ? variant : ButtonVariant.DEFAULT;
+        }
+
+        @Override
+        public void installUI(JComponent c) {
+            super.installUI(c);
+            AbstractButton b = (AbstractButton) c;
+            b.addMouseListener(new MouseAdapter() {
+                @Override
+                public void mouseEntered(MouseEvent e) {
+                    hover = true;
+                    b.repaint();
+                }
+                @Override
+                public void mouseExited(MouseEvent e) {
+                    hover = false;
+                    b.repaint();
+                }
+            });
+        }
+
+        @Override
+        public void paint(Graphics g, JComponent c) {
+            AbstractButton b = (AbstractButton) c;
+            Graphics2D g2 = (Graphics2D) g.create();
+            g2.setRenderingHint(RenderingHints.KEY_ANTIALIASING, RenderingHints.VALUE_ANTIALIAS_ON);
+
+            int w = c.getWidth();
+            int h = c.getHeight();
+
+            ButtonModel model = b.getModel();
+            boolean pressed = model.isArmed() && model.isPressed();
+            boolean enabled = b.isEnabled();
+
+            UITheme t = ThemeManager.getTheme();
+            Color bg = enabled ? ThemeManager.getButtonBg(variant, t, hover, pressed) : (t == UITheme.DARK ? new Color(40, 40, 40) : new Color(220, 220, 220));
+            Color fg = enabled ? ThemeManager.getButtonFg(variant, t) : ThemeManager.getFgDisabled(t);
+
+            // Background
+            g2.setColor(bg);
+            g2.fillRoundRect(0, 0, w, h, 6, 6);
+
+            // Border
+            if (variant == ButtonVariant.DEFAULT || variant == ButtonVariant.CANCEL) {
+                g2.setColor(ThemeManager.getBorder(t));
+                g2.drawRoundRect(0, 0, w - 1, h - 1, 6, 6);
+            }
+
+            // Text / Icon
+            FontMetrics fm = g2.getFontMetrics(b.getFont());
+            String text = b.getText();
+            if (text != null && !text.isEmpty()) {
+                g2.setColor(fg);
+                g2.setFont(b.getFont());
+                int tx = (w - fm.stringWidth(text)) / 2;
+                int ty = (h - fm.getHeight()) / 2 + fm.getAscent();
+                g2.drawString(text, tx, ty);
+            }
+
+            g2.dispose();
+        }
+    }
+
+    public static class StyledMenuBarUI extends BasicMenuBarUI {
+        @Override
+        public void paint(Graphics g, JComponent c) {
+            g.setColor(ThemeManager.getMenuBarBg());
+            g.fillRect(0, 0, c.getWidth(), c.getHeight());
+        }
+    }
+
+    public static class StyledMenuUI extends BasicMenuUI {
+        @Override
+        protected void paintBackground(Graphics g, JMenuItem menuItem, Color bgColor) {
+            ButtonModel model = menuItem.getModel();
+            if (model.isArmed() || model.isSelected()) {
+                g.setColor(ThemeManager.getMenuItemHoverBg());
+                g.fillRect(0, 0, menuItem.getWidth(), menuItem.getHeight());
+            } else {
+                g.setColor(ThemeManager.getMenuBarBg());
+                g.fillRect(0, 0, menuItem.getWidth(), menuItem.getHeight());
+            }
+        }
+
+        @Override
+        protected void paintText(Graphics g, JMenuItem menuItem, Rectangle textRect, String text) {
+            ButtonModel model = menuItem.getModel();
+            if (model.isArmed() || model.isSelected()) {
+                g.setColor(ThemeManager.getMenuItemHoverFg());
+            } else {
+                g.setColor(ThemeManager.getMenuBarFg());
+            }
+            super.paintText(g, menuItem, textRect, text);
+        }
+    }
+
+    public static class StyledMenuItemUI extends BasicMenuItemUI {
+        @Override
+        protected void paintBackground(Graphics g, JMenuItem menuItem, Color bgColor) {
+            ButtonModel model = menuItem.getModel();
+            if (model.isArmed() || model.isSelected()) {
+                g.setColor(ThemeManager.getSelectionBg());
+                g.fillRect(0, 0, menuItem.getWidth(), menuItem.getHeight());
+            } else {
+                g.setColor(ThemeManager.getMenuPopupBg());
+                g.fillRect(0, 0, menuItem.getWidth(), menuItem.getHeight());
+            }
+        }
+
+        @Override
+        protected void paintText(Graphics g, JMenuItem menuItem, Rectangle textRect, String text) {
+            ButtonModel model = menuItem.getModel();
+            if (model.isArmed() || model.isSelected()) {
+                g.setColor(ThemeManager.getSelectionFg());
+            } else {
+                g.setColor(ThemeManager.getMenuItemFg());
+            }
+            super.paintText(g, menuItem, textRect, text);
+        }
+    }
+
+    public static class StyledPopupMenuUI extends BasicPopupMenuUI {
+        @Override
+        public void paint(Graphics g, JComponent c) {
+            g.setColor(ThemeManager.getMenuPopupBg());
+            g.fillRect(0, 0, c.getWidth(), c.getHeight());
+        }
+    }
+
+    public static class StyledTabbedPaneUI extends BasicTabbedPaneUI {
+        @Override
+        protected void installDefaults() {
+            super.installDefaults();
+            tabInsets = new Insets(6, 16, 6, 16);
+            selectedTabPadInsets = new Insets(2, 2, 2, 2);
+            tabAreaInsets = new Insets(4, 4, 0, 4);
+        }
+
+        @Override
+        protected void paintTabBackground(Graphics g, int tabPlacement, int tabIndex, int x, int y, int w, int h, boolean isSelected) {
+            Graphics2D g2 = (Graphics2D) g.create();
+            g2.setRenderingHint(RenderingHints.KEY_ANTIALIASING, RenderingHints.VALUE_ANTIALIAS_ON);
+            g2.setColor(isSelected ? ThemeManager.getTabSelectedBg() : ThemeManager.getTabBg());
+            g2.fillRoundRect(x, y, w, h + 4, 6, 6);
+            g2.setColor(ThemeManager.getBorder());
+            g2.drawRoundRect(x, y, w - 1, h + 4, 6, 6);
+            g2.dispose();
+        }
+
+        @Override
+        protected void paintText(Graphics g, int tabPlacement, Font font, FontMetrics metrics, int tabIndex, String title, Rectangle textRect, boolean isSelected) {
+            g.setFont(font);
+            g.setColor(isSelected ? ThemeManager.getTabSelectedFg() : ThemeManager.getTabFg());
+            g.drawString(title, textRect.x, textRect.y + metrics.getAscent());
+        }
+
+        @Override
+        protected void paintContentBorder(Graphics g, int tabPlacement, int selectedIndex) {
+            int width = tabPane.getWidth();
+            int height = tabPane.getHeight();
+            Insets insets = tabPane.getInsets();
+            int x = insets.left;
+            int y = insets.top + calculateTabAreaHeight(tabPlacement, runCount, maxTabHeight);
+            int w = width - insets.right - insets.left;
+            int h = height - insets.top - insets.bottom - calculateTabAreaHeight(tabPlacement, runCount, maxTabHeight);
+
+            g.setColor(ThemeManager.getTabSelectedBg());
+            g.fillRect(x, y, w, h);
+            g.setColor(ThemeManager.getBorder());
+            g.drawRect(x, y, w - 1, h - 1);
+        }
+    }
+}
diff --git a/j3270/src/main/java/haus/nightmare/j3270/ui/UITheme.java b/j3270/src/main/java/haus/nightmare/j3270/ui/UITheme.java
new file mode 100644
index 0000000..7afb1ed
--- /dev/null
+++ b/j3270/src/main/java/haus/nightmare/j3270/ui/UITheme.java
@@ -0,0 +1,33 @@
+package haus.nightmare.j3270.ui;
+
+/**
+ * Supported UI themes for the j3270 Java desktop interface.
+ */
+public enum UITheme {
+    DARK("Dark Mode"),
+    LIGHT("Light Mode");
+
+    private final String displayName;
+
+    UITheme(String displayName) {
+        this.displayName = displayName;
+    }
+
+    public String getDisplayName() {
+        return displayName;
+    }
+
+    @Override
+    public String toString() {
+        return displayName;
+    }
+
+    public static UITheme fromString(String name) {
+        if (name == null) return DARK;
+        String s = name.trim().toUpperCase();
+        if ("LIGHT".equals(s) || "LIGHT MODE".equals(s) || "LIGHT_MODE".equals(s)) {
+            return LIGHT;
+        }
+        return DARK;
+    }
+}
diff --git a/j3270/src/main/java/haus/nightmare/j3270/ui/UntrustedCertificateDialog.java b/j3270/src/main/java/haus/nightmare/j3270/ui/UntrustedCertificateDialog.java
index baea7ee..5f909ca 100644
--- a/j3270/src/main/java/haus/nightmare/j3270/ui/UntrustedCertificateDialog.java
+++ b/j3270/src/main/java/haus/nightmare/j3270/ui/UntrustedCertificateDialog.java
@@ -26,25 +26,24 @@ public class UntrustedCertificateDialog extends JDialog {
     private void buildUI(String host, int port, X509Certificate[] chain, CertificateException exception) {
         JPanel mainPanel = new JPanel(new BorderLayout(12, 12));
         mainPanel.setBorder(BorderFactory.createEmptyBorder(16, 16, 16, 16));
-        mainPanel.setBackground(new Color(30, 30, 30));
 
         // Header
         JPanel headerPanel = new JPanel(new FlowLayout(FlowLayout.LEFT, 10, 0));
-        headerPanel.setBackground(new Color(30, 30, 30));
+        headerPanel.setOpaque(false);
         JLabel iconLabel = new JLabel("⚠️");
         iconLabel.setFont(new Font(Font.SANS_SERIF, Font.PLAIN, 28));
         headerPanel.add(iconLabel);
 
         JPanel titleBox = new JPanel(new GridLayout(2, 1, 0, 2));
-        titleBox.setBackground(new Color(30, 30, 30));
+        titleBox.setOpaque(false);
         JLabel titleLabel = new JLabel("Untrusted SSL Certificate");
         titleLabel.setFont(new Font(Font.SANS_SERIF, Font.BOLD, 16));
-        titleLabel.setForeground(new Color(255, 180, 80));
+        titleLabel.setForeground(ThemeManager.getOiaFgWarn());
         titleBox.add(titleLabel);
 
         JLabel subtitleLabel = new JLabel("The server certificate for " + host + ":" + port + " could not be verified.");
         subtitleLabel.setFont(new Font(Font.SANS_SERIF, Font.PLAIN, 12));
-        subtitleLabel.setForeground(new Color(180, 180, 180));
+        subtitleLabel.setForeground(ThemeManager.getFgMuted());
         titleBox.add(subtitleLabel);
         headerPanel.add(titleBox);
         mainPanel.add(headerPanel, BorderLayout.NORTH);
@@ -71,30 +70,27 @@ public class UntrustedCertificateDialog extends JDialog {
         JTextArea detailsArea = new JTextArea(sb.toString());
         detailsArea.setEditable(false);
         detailsArea.setFont(new Font(Font.MONOSPACED, Font.PLAIN, 12));
-        detailsArea.setBackground(new Color(20, 20, 20));
-        detailsArea.setForeground(new Color(210, 210, 210));
+        ThemeManager.styleTextArea(detailsArea);
         detailsArea.setBorder(BorderFactory.createEmptyBorder(8, 8, 8, 8));
 
         JScrollPane scrollPane = new JScrollPane(detailsArea);
         scrollPane.setPreferredSize(new Dimension(520, 260));
-        scrollPane.setBorder(BorderFactory.createLineBorder(new Color(60, 60, 60)));
+        ThemeManager.styleScrollPane(scrollPane);
         mainPanel.add(scrollPane, BorderLayout.CENTER);
 
         // Buttons
         JPanel buttonPanel = new JPanel(new FlowLayout(FlowLayout.RIGHT, 10, 0));
-        buttonPanel.setBackground(new Color(30, 30, 30));
+        buttonPanel.setOpaque(false);
 
         JButton cancelBtn = new JButton("Cancel Connection");
-        cancelBtn.setBackground(new Color(60, 60, 60));
-        cancelBtn.setForeground(new Color(220, 220, 220));
+        ThemeManager.styleButton(cancelBtn, ThemeManager.ButtonVariant.CANCEL);
         cancelBtn.addActionListener(e -> {
             accepted = false;
             dispose();
         });
 
         JButton trustBtn = new JButton("Connect Anyway");
-        trustBtn.setBackground(new Color(180, 100, 40));
-        trustBtn.setForeground(Color.WHITE);
+        ThemeManager.styleButton(trustBtn, ThemeManager.ButtonVariant.DANGER);
         trustBtn.setFont(new Font(Font.SANS_SERIF, Font.BOLD, 13));
         trustBtn.addActionListener(e -> {
             accepted = true;
@@ -106,6 +102,7 @@ public class UntrustedCertificateDialog extends JDialog {
         mainPanel.add(buttonPanel, BorderLayout.SOUTH);
 
         setContentPane(mainPanel);
+        ThemeManager.applyThemeToWindow(this);
         getRootPane().setDefaultButton(trustBtn);
     }
 
diff --git a/j3270/src/test/java/haus/nightmare/j3270/ui/ThemeManagerTest.java b/j3270/src/test/java/haus/nightmare/j3270/ui/ThemeManagerTest.java
new file mode 100644
index 0000000..97e9137
--- /dev/null
+++ b/j3270/src/test/java/haus/nightmare/j3270/ui/ThemeManagerTest.java
@@ -0,0 +1,213 @@
+package haus.nightmare.j3270.ui;
+
+import haus.nightmare.j3270.config.Settings;
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
+
+import javax.swing.*;
+import javax.swing.border.Border;
+import javax.swing.table.DefaultTableModel;
+import java.awt.*;
+import java.io.File;
+import java.io.PrintWriter;
+import java.nio.file.Files;
+import java.util.concurrent.atomic.AtomicReference;
+
+import static org.junit.jupiter.api.Assertions.*;
+
+public class ThemeManagerTest {
+
+    @BeforeEach
+    public void setup() {
+        ThemeManager.setTheme(UITheme.DARK);
+    }
+
+    @Test
+    public void testUIThemeEnum() {
+        assertEquals("Dark Mode", UITheme.DARK.getDisplayName());
+        assertEquals("Light Mode", UITheme.LIGHT.getDisplayName());
+
+        assertEquals(UITheme.DARK, UITheme.fromString("DARK"));
+        assertEquals(UITheme.DARK, UITheme.fromString("dark"));
+        assertEquals(UITheme.DARK, UITheme.fromString("Dark Mode"));
+        assertEquals(UITheme.LIGHT, UITheme.fromString("LIGHT"));
+        assertEquals(UITheme.LIGHT, UITheme.fromString("light"));
+        assertEquals(UITheme.LIGHT, UITheme.fromString("Light Mode"));
+        assertEquals(UITheme.DARK, UITheme.fromString("invalid_value"));
+    }
+
+    @Test
+    public void testColorTokensContrast() {
+        for (UITheme theme : UITheme.values()) {
+            Color bg = ThemeManager.getBgMain(theme);
+            Color fg = ThemeManager.getFgMain(theme);
+            assertNotNull(bg);
+            assertNotNull(fg);
+
+            // Compute luminance contrast
+            double bgLum = (0.299 * bg.getRed() + 0.587 * bg.getGreen() + 0.114 * bg.getBlue());
+            double fgLum = (0.299 * fg.getRed() + 0.587 * fg.getGreen() + 0.114 * fg.getBlue());
+            double lumDiff = Math.abs(bgLum - fgLum);
+
+            // Minimum luminance difference to guarantee readability
+            assertTrue(lumDiff > 120, "Theme " + theme + " text contrast luminance difference " + lumDiff + " must be > 120");
+
+            // Verify Menu Bar colors
+            Color menuBg = ThemeManager.getMenuBarBg(theme);
+            Color menuFg = ThemeManager.getMenuItemFg(theme);
+            double menuBgLum = (0.299 * menuBg.getRed() + 0.587 * menuBg.getGreen() + 0.114 * menuBg.getBlue());
+            double menuFgLum = (0.299 * menuFg.getRed() + 0.587 * menuFg.getGreen() + 0.114 * menuFg.getBlue());
+            assertTrue(Math.abs(menuBgLum - menuFgLum) > 100, "Menu contrast in " + theme + " must be high");
+
+            // Verify Status Bar colors
+            Color sbBg = ThemeManager.getStatusBarBg(theme);
+            Color sbNormal = ThemeManager.getOiaFgNormal(theme);
+            assertNotNull(sbBg);
+            assertNotNull(sbNormal);
+
+            // Verify Button colors
+            Color btnDefBg = ThemeManager.getButtonBg(ThemeManager.ButtonVariant.DEFAULT, theme);
+            Color btnDefFg = ThemeManager.getButtonFg(ThemeManager.ButtonVariant.DEFAULT, theme);
+            assertNotNull(btnDefBg);
+            assertNotNull(btnDefFg);
+
+            Color btnPriBg = ThemeManager.getButtonBg(ThemeManager.ButtonVariant.PRIMARY, theme);
+            Color btnPriFg = ThemeManager.getButtonFg(ThemeManager.ButtonVariant.PRIMARY, theme);
+            assertNotNull(btnPriBg);
+            assertNotNull(btnPriFg);
+        }
+    }
+
+    @Test
+    public void testThemeChangeListeners() {
+        AtomicReference<UITheme> notifiedTheme = new AtomicReference<>(null);
+        ThemeManager.addThemeChangeListener(notifiedTheme::set);
+
+        ThemeManager.setTheme(UITheme.LIGHT);
+        assertEquals(UITheme.LIGHT, ThemeManager.getTheme());
+        assertEquals(UITheme.LIGHT, notifiedTheme.get());
+        assertTrue(ThemeManager.isLight());
+        assertFalse(ThemeManager.isDark());
+
+        ThemeManager.setTheme(UITheme.DARK);
+        assertEquals(UITheme.DARK, ThemeManager.getTheme());
+        assertEquals(UITheme.DARK, notifiedTheme.get());
+        assertTrue(ThemeManager.isDark());
+        assertFalse(ThemeManager.isLight());
+    }
+
+    @Test
+    public void testComponentStyling() {
+        JButton btn = new JButton("Test");
+        ThemeManager.styleButton(btn, ThemeManager.ButtonVariant.PRIMARY);
+        assertNotNull(btn.getUI());
+        assertTrue(btn.getUI() instanceof ThemeManager.StyledButtonUI);
+
+        JTextField tf = new JTextField("Test");
+        ThemeManager.styleTextField(tf);
+        assertNotNull(tf.getCaretColor());
+
+        JTextArea ta = new JTextArea("Test area");
+        ThemeManager.styleTextArea(ta);
+        assertNotNull(ta.getCaretColor());
+
+        JComboBox<String> cb = new JComboBox<>(new String[]{"A", "B"});
+        ThemeManager.styleComboBox(cb);
+        assertNotNull(cb.getUI());
+
+        JTable table = new JTable(new DefaultTableModel(new Object[]{"Col1"}, 1));
+        ThemeManager.styleTable(table);
+        assertNotNull(table.getSelectionBackground());
+
+        JTabbedPane tp = new JTabbedPane();
+        tp.addTab("Tab1", new JPanel());
+        ThemeManager.styleTabbedPane(tp);
+        assertNotNull(tp.getUI());
+
+        JMenuBar mb = new JMenuBar();
+        ThemeManager.styleMenuBar(mb);
+
+        JMenu menu = new JMenu("File");
+        ThemeManager.styleMenu(menu);
+
+        JMenuItem mi = new JMenuItem("Open");
+        ThemeManager.styleMenuItem(mi);
+
+        JPopupMenu popup = new JPopupMenu();
+        ThemeManager.stylePopupMenu(popup);
+
+        JCheckBox chk = new JCheckBox("Check");
+        ThemeManager.styleCheckBox(chk);
+
+        JRadioButton rb = new JRadioButton("Radio");
+        ThemeManager.styleRadioButton(rb);
+
+        Border tb = ThemeManager.createTitledBorder("Title");
+        assertNotNull(tb);
+    }
+
+    @Test
+    public void testRecursiveApplyTheme() {
+        JPanel root = new JPanel(new BorderLayout());
+        JButton b = new JButton("OK");
+        JTextField f = new JTextField("Data");
+        JTabbedPane tp = new JTabbedPane();
+        JPanel tabContent = new JPanel();
+        JLabel lbl = new JLabel("Label");
+        tabContent.add(lbl);
+        tp.addTab("T1", tabContent);
+
+        root.add(b, BorderLayout.NORTH);
+        root.add(f, BorderLayout.CENTER);
+        root.add(tp, BorderLayout.SOUTH);
+
+        ThemeManager.setTheme(UITheme.LIGHT);
+        ThemeManager.applyTheme(root);
+
+        assertEquals(ThemeManager.getBgPanel(UITheme.LIGHT), root.getBackground());
+        assertEquals(ThemeManager.getFgMain(UITheme.LIGHT), lbl.getForeground());
+
+        ThemeManager.setTheme(UITheme.DARK);
+        ThemeManager.applyTheme(root);
+
+        assertEquals(ThemeManager.getBgPanel(UITheme.DARK), root.getBackground());
+        assertEquals(ThemeManager.getFgMain(UITheme.DARK), lbl.getForeground());
+    }
+
+    @Test
+    public void testSettingsPersistence() throws Exception {
+        Settings.setJavaUiTheme(UITheme.LIGHT);
+        assertEquals(UITheme.LIGHT, Settings.getJavaUiTheme());
+
+        File tmpIni = File.createTempFile("j3270_test_config", ".ini");
+        tmpIni.deleteOnExit();
+
+        try {
+            // Write INI file with javaUiTheme = dark
+            try (PrintWriter pw = new PrintWriter(tmpIni)) {
+                pw.println("[j3270]");
+                pw.println("javaUiTheme = dark");
+                pw.println("fontFamily = Monospaced");
+                pw.println("fontSize = 16");
+            }
+
+            Settings.loadFromIniFile(tmpIni.getAbsolutePath());
+            assertEquals(UITheme.DARK, Settings.getJavaUiTheme());
+
+            // Switch to light and export
+            Settings.setJavaUiTheme(UITheme.LIGHT);
+            File exportFile = File.createTempFile("j3270_export_config", ".ini");
+            exportFile.deleteOnExit();
+
+            Settings.exportToIniFile(exportFile.getAbsolutePath());
+            String exportedContent = new String(Files.readAllBytes(exportFile.toPath()));
+            assertTrue(exportedContent.toLowerCase().contains("javauitheme = light"));
+
+            // Reload exported file
+            Settings.loadFromIniFile(exportFile.getAbsolutePath());
+            assertEquals(UITheme.LIGHT, Settings.getJavaUiTheme());
+        } finally {
+            tmpIni.delete();
+        }
+    }
+}
diff --git a/lib3270j/src/main/java/haus/nightmare/lib3270j/ConnectionConfig.java b/lib3270j/src/main/java/haus/nightmare/lib3270j/ConnectionConfig.java
index b898db1..237f1eb 100644
--- a/lib3270j/src/main/java/haus/nightmare/lib3270j/ConnectionConfig.java
+++ b/lib3270j/src/main/java/haus/nightmare/lib3270j/ConnectionConfig.java
@@ -5,6 +5,10 @@ package haus.nightmare.lib3270j;
  */
 public class ConnectionConfig {
 
+    public enum ProxyType {
+        NONE, HTTP, SOCKS4, SOCKS5
+    }
+
     private String host;
     private int port = 23;
     private TerminalModel model = TerminalModel.IBM_3279_4;
@@ -28,6 +32,21 @@ public class ConnectionConfig {
     private haus.nightmare.lib3270j.graphics.GraphicsMode graphicsMode = haus.nightmare.lib3270j.graphics.GraphicsMode.BOTH;
     private String codePage = "037";
     private String associatedPrinterLu = null;
+    private boolean nvtLocalEcho = false;
+
+    // Proxy configuration
+    private ProxyType proxyType = ProxyType.NONE;
+    private String proxyHost = null;
+    private int proxyPort = 0;
+    private String proxyUsername = null;
+    private String proxyPassword = null;
+
+    // STARTTLS (Telnet Option 46) dynamic socket elevation
+    private boolean startTlsEnabled = true;
+
+    // RFC 1572 / RFC 2877 Environment variables (Express Logon)
+    private java.util.Map<String, String> environmentVariables = new java.util.LinkedHashMap<>();
+    private java.util.Map<String, String> userVariables = new java.util.LinkedHashMap<>();
 
     public ConnectionConfig() {}
 
@@ -101,6 +120,9 @@ public class ConnectionConfig {
         this.codePage = (codePage != null && !codePage.trim().isEmpty()) ? codePage.trim() : "037";
     }
 
+    public boolean isNvtLocalEcho() { return nvtLocalEcho; }
+    public void setNvtLocalEcho(boolean nvtLocalEcho) { this.nvtLocalEcho = nvtLocalEcho; }
+
     public String getTerminalName()           { return terminalName; }
     public void setTerminalName(String name)  { this.terminalName = name; }
 
@@ -134,9 +156,58 @@ public class ConnectionConfig {
         this.dynamicCols = cols;
     }
 
+    public ProxyType getProxyType() { return proxyType; }
+    public void setProxyType(ProxyType proxyType) { this.proxyType = proxyType != null ? proxyType : ProxyType.NONE; }
+
+    public String getProxyHost() { return proxyHost; }
+    public void setProxyHost(String proxyHost) { this.proxyHost = proxyHost; }
+
+    public int getProxyPort() { return proxyPort; }
+    public void setProxyPort(int proxyPort) { this.proxyPort = proxyPort; }
+
+    public String getProxyUsername() { return proxyUsername; }
+    public void setProxyUsername(String proxyUsername) { this.proxyUsername = proxyUsername; }
+
+    public String getProxyPassword() { return proxyPassword; }
+    public void setProxyPassword(String proxyPassword) { this.proxyPassword = proxyPassword; }
+
+    public void setProxy(ProxyType type, String host, int port, String username, String password) {
+        this.proxyType = type != null ? type : ProxyType.NONE;
+        this.proxyHost = host;
+        this.proxyPort = port;
+        this.proxyUsername = username;
+        this.proxyPassword = password;
+    }
+
+    public boolean isStartTlsEnabled() { return startTlsEnabled; }
+    public void setStartTlsEnabled(boolean enabled) { this.startTlsEnabled = enabled; }
+
+    public java.util.Map<String, String> getEnvironmentVariables() { return environmentVariables; }
+    public void setEnvironmentVariables(java.util.Map<String, String> vars) {
+        this.environmentVariables = (vars != null) ? new java.util.LinkedHashMap<>(vars) : new java.util.LinkedHashMap<>();
+    }
+    public void setEnvironmentVariable(String name, String value) {
+        if (name != null) {
+            if (value != null) this.environmentVariables.put(name, value);
+            else this.environmentVariables.remove(name);
+        }
+    }
+
+    public java.util.Map<String, String> getUserVariables() { return userVariables; }
+    public void setUserVariables(java.util.Map<String, String> vars) {
+        this.userVariables = (vars != null) ? new java.util.LinkedHashMap<>(vars) : new java.util.LinkedHashMap<>();
+    }
+    public void setUserVariable(String name, String value) {
+        if (name != null) {
+            if (value != null) this.userVariables.put(name, value);
+            else this.userVariables.remove(name);
+        }
+    }
+
     /**
      * Parse a host connection string which may include prefixes for TLS (e.g. "L:host:port", "ssl:host:port", "y:host:port"),
-     * plain TN3270 (e.g. "P:host:port", "plain:host:port", "non-e:host:port"), or standard "host:port" formats.
+     * plain TN3270 (e.g. "P:host:port", "plain:host:port", "non-e:host:port"), proxy flags (e.g. "--proxy=http://proxy:8080 host:23"),
+     * or standard "host:port" formats.
      */
     public static ConnectionConfig parseHostString(String hostStr, int defaultPort, TerminalModel defaultModel) {
         if (hostStr == null || hostStr.trim().isEmpty()) {
@@ -146,6 +217,50 @@ public class ConnectionConfig {
         boolean tls = false;
         boolean tn3270e = true;
 
+        // Parse --proxy=<url> or -proxy=<url> flags
+        ProxyType pType = ProxyType.NONE;
+        String pHost = null;
+        int pPort = 0;
+        String pUser = null;
+        String pPass = null;
+
+        String[] tokens = s.split("\\s+");
+        StringBuilder remaining = new StringBuilder();
+        for (String tok : tokens) {
+            if (tok.startsWith("--proxy=") || tok.startsWith("-proxy=")) {
+                String proxyUrl = tok.substring(tok.indexOf('=') + 1).trim();
+                try {
+                    java.net.URI uri = new java.net.URI(proxyUrl);
+                    String scheme = uri.getScheme() != null ? uri.getScheme().toLowerCase() : "http";
+                    if (scheme.equals("http") || scheme.equals("https")) {
+                        pType = ProxyType.HTTP;
+                        pPort = uri.getPort() > 0 ? uri.getPort() : 8080;
+                    } else if (scheme.equals("socks4") || scheme.equals("socks4a")) {
+                        pType = ProxyType.SOCKS4;
+                        pPort = uri.getPort() > 0 ? uri.getPort() : 1080;
+                    } else if (scheme.equals("socks5") || scheme.equals("socks")) {
+                        pType = ProxyType.SOCKS5;
+                        pPort = uri.getPort() > 0 ? uri.getPort() : 1080;
+                    }
+                    pHost = uri.getHost();
+                    String userInfo = uri.getUserInfo();
+                    if (userInfo != null) {
+                        int colon = userInfo.indexOf(':');
+                        if (colon >= 0) {
+                            pUser = userInfo.substring(0, colon);
+                            pPass = userInfo.substring(colon + 1);
+                        } else {
+                            pUser = userInfo;
+                        }
+                    }
+                } catch (Exception ignored) {}
+            } else {
+                if (remaining.length() > 0) remaining.append(" ");
+                remaining.append(tok);
+            }
+        }
+        s = remaining.toString().trim();
+
         // Parse chained x3270-style prefixes (e.g. "L:P:host:port" or "P:host:port")
         boolean prefixFound = true;
         while (prefixFound) {
@@ -200,6 +315,9 @@ public class ConnectionConfig {
         ConnectionConfig config = new ConnectionConfig(host, port, defaultModel != null ? defaultModel : TerminalModel.IBM_3279_4);
         config.setUseTls(tls);
         config.setTn3270eEnabled(tn3270e);
+        if (pType != ProxyType.NONE && pHost != null) {
+            config.setProxy(pType, pHost, pPort, pUser, pPass);
+        }
         return config;
     }
 
diff --git a/lib3270j/src/main/java/haus/nightmare/lib3270j/Telnet3270Client.java b/lib3270j/src/main/java/haus/nightmare/lib3270j/Telnet3270Client.java
index 22fb045..2046584 100644
--- a/lib3270j/src/main/java/haus/nightmare/lib3270j/Telnet3270Client.java
+++ b/lib3270j/src/main/java/haus/nightmare/lib3270j/Telnet3270Client.java
@@ -118,6 +118,14 @@ public class Telnet3270Client {
         dsProcessor.addScreenUpdateListener(l);
     }
 
+    public void addSCSInboundListener(haus.nightmare.lib3270j.listener.SCSInboundListener l) {
+        fsm.addSCSInboundListener(l);
+    }
+
+    public void removeSCSInboundListener(haus.nightmare.lib3270j.listener.SCSInboundListener l) {
+        fsm.removeSCSInboundListener(l);
+    }
+
     // ========== Screen access ==========
 
     /** Get the screen buffer for rendering. */
diff --git a/lib3270j/src/main/java/haus/nightmare/lib3270j/datastream/DataStreamProcessor.java b/lib3270j/src/main/java/haus/nightmare/lib3270j/datastream/DataStreamProcessor.java
index 0352ec5..aa1ea8a 100644
--- a/lib3270j/src/main/java/haus/nightmare/lib3270j/datastream/DataStreamProcessor.java
+++ b/lib3270j/src/main/java/haus/nightmare/lib3270j/datastream/DataStreamProcessor.java
@@ -144,6 +144,9 @@ public class DataStreamProcessor {
                         int oldCols = screen.getCols();
                         screen.erase(false);
                         graphicsPlane.clear();
+                        if (gocaDecoder != null) {
+                            gocaDecoder.setGraphicsCursorActive(false);
+                        }
                         processWrite(data, offset, length, true);
                         if (oldRows != screen.getRows() || oldCols != screen.getCols()) {
                             notifyScreenSizeChanged();
@@ -161,6 +164,9 @@ public class DataStreamProcessor {
                         int oldCols = screen.getCols();
                         screen.erase(true);
                         graphicsPlane.clear();
+                        if (gocaDecoder != null) {
+                            gocaDecoder.setGraphicsCursorActive(false);
+                        }
                         processWrite(data, offset, length, true);
                         if (oldRows != screen.getRows() || oldCols != screen.getCols()) {
                             notifyScreenSizeChanged();
diff --git a/lib3270j/src/main/java/haus/nightmare/lib3270j/ecl/ECLPS.java b/lib3270j/src/main/java/haus/nightmare/lib3270j/ecl/ECLPS.java
index 2c43944..f6e5107 100644
--- a/lib3270j/src/main/java/haus/nightmare/lib3270j/ecl/ECLPS.java
+++ b/lib3270j/src/main/java/haus/nightmare/lib3270j/ecl/ECLPS.java
@@ -33,6 +33,19 @@ public class ECLPS implements ECLConstants {
         return fieldList;
     }
 
+    private boolean nvtMode = false;
+
+    public boolean isNVTmode() {
+        if (inputProcessor != null && inputProcessor.isNvtMode()) {
+            return true;
+        }
+        return nvtMode;
+    }
+
+    public void setNVTmode(boolean nvt) {
+        this.nvtMode = nvt;
+    }
+
     public int getSize()     { return screen.getRows() * screen.getCols(); }
     public int getRows()     { return screen.getRows(); }
     public int getCols()     { return screen.getCols(); }
diff --git a/lib3270j/src/main/java/haus/nightmare/lib3270j/input/InputProcessor.java b/lib3270j/src/main/java/haus/nightmare/lib3270j/input/InputProcessor.java
index 4c82018..bec4f98 100644
--- a/lib3270j/src/main/java/haus/nightmare/lib3270j/input/InputProcessor.java
+++ b/lib3270j/src/main/java/haus/nightmare/lib3270j/input/InputProcessor.java
@@ -8,6 +8,7 @@ import haus.nightmare.lib3270j.protocol.TelnetConstants;
 import static haus.nightmare.lib3270j.protocol.DS3270Constants.*;
 
 import java.io.ByteArrayOutputStream;
+import java.io.IOException;
 import java.util.logging.Logger;
 
 /**
@@ -31,6 +32,14 @@ public class InputProcessor {
         this.fsm = fsm;
     }
 
+    public TelnetFSM getFsm() {
+        return fsm;
+    }
+
+    public boolean isNvtMode() {
+        return fsm != null && fsm.getConnectionState() != null && fsm.getConnectionState().isNvt();
+    }
+
     private haus.nightmare.lib3270j.graphics.GraphicsPlane graphicsPlane;
     private haus.nightmare.lib3270j.graphics.GocaDecoder gocaDecoder;
 
@@ -95,6 +104,15 @@ public class InputProcessor {
     public void typeCharacter(char ch) {
         if (keyboardLocked) return;
 
+        if (isNvtMode()) {
+            try {
+                fsm.sendNVTChar(ch);
+            } catch (IOException e) {
+                log.warning("Failed to send NVT character: " + e.getMessage());
+            }
+            return;
+        }
+
         int size = screen.getRows() * screen.getCols();
         if (size <= 0) return;
         int baddr = screen.getCursorAddress();
@@ -237,86 +255,6 @@ public class InputProcessor {
             return;
         }
 
-        if (gocaDecoder != null && gocaDecoder.isGraphicsCursorActive()) {
-            int gx = gocaDecoder.getGraphicCursorX();
-            int gy = gocaDecoder.getGraphicCursorY();
-            int cols = (screen != null && screen.getCols() > 0) ? screen.getCols() : 80;
-            int numRows = (screen != null && screen.getRows() > 0) ? screen.getRows() : 24;
-            int cursorAddr = screen != null ? screen.getCursorAddress() : 0;
-            int row = cursorAddr / cols;
-            int col = cursorAddr % cols;
-
-            byte[] sf = haus.nightmare.lib3270j.graphics.GraphicInputBuilder.buildGraphicInput(
-                gx, gy, row, col, aidCode, false, false, false
-            );
-
-            StringBuilder sfHex = new StringBuilder();
-            for (byte b : sf) {
-                sfHex.append(String.format("%02X ", b & 0xFF));
-            }
-            log.info(String.format(
-                "sendAid (graphic): goca=(%d, %d) row=%d col=%d cursorAddr=%d aid=0x%02X SF_HEX=[%s]",
-                gx, gy, row, col, cursorAddr, aidCode, sfHex.toString().trim()
-            ));
-
-            ByteArrayOutputStream out = new ByteArrayOutputStream();
-
-            // Structured Field AID (0x88) + 56-byte Graphic Input SF
-            out.write(AID_SF);
-            try {
-                out.write(sf);
-            } catch (java.io.IOException ignored) {}
-
-            // Trailing AID + cursor address
-            out.write(aidCode);
-            byte[] caddr = encodeAddress(cursorAddr, numRows, cols);
-            out.write(caddr[0] & 0xFF);
-            out.write(caddr[1] & 0xFF);
-
-            if (aidCode == AID_PA1 || aidCode == AID_PA2 || aidCode == AID_PA3) {
-                sendAidResponse(out.toByteArray());
-                return;
-            }
-
-            if (screen.isFormatted()) {
-                int size = screen.getRows() * screen.getCols();
-                for (int i = 0; i < size; i++) {
-                    ExtendedAttribute ea = screen.getCell(i);
-                    if (ea.isFieldAttribute() && faIsModified(ea.fa & 0xFF)) {
-                        int fieldStart = (i + 1) % size;
-
-                        // Always send SBA and address of first character in field
-                        out.write(ORDER_SBA);
-                        byte[] addr = encodeAddress(fieldStart, screen.getRows(), screen.getCols());
-                        out.write(addr[0] & 0xFF);
-                        out.write(addr[1] & 0xFF);
-
-                        // Send all non-null characters in field (suppressing 0x00)
-                        int pos = fieldStart;
-                        while (!screen.getCell(pos).isFieldAttribute()) {
-                            int b = screen.getCell(pos).ec & 0xFF;
-                            if (b != 0x00) {
-                                out.write(b);
-                            }
-                            pos = (pos + 1) % size;
-                            if (pos == fieldStart) break;
-                        }
-                    }
-                }
-            } else {
-                int size = screen.getRows() * screen.getCols();
-                for (int i = 0; i < size; i++) {
-                    int b = screen.getCell(i).ec & 0xFF;
-                    if (b != 0x00) {
-                        out.write(b);
-                    }
-                }
-            }
-
-            sendAidResponse(out.toByteArray());
-            return;
-        }
-
         if (aidCode == AID_PA1 || aidCode == AID_PA2 || aidCode == AID_PA3) {
             // PA keys: send AID + optional PID + cursor address only (no modified data)
             ByteArrayOutputStream out = new ByteArrayOutputStream();
@@ -863,6 +801,16 @@ public class InputProcessor {
      * Equivalent to emulate_input() in x3270.
      */
     public void emulateInput(String text) {
+        if (text == null) return;
+        if (isNvtMode()) {
+            try {
+                fsm.sendNVTString(text);
+            } catch (IOException e) {
+                log.warning("Failed to send NVT input: " + e.getMessage());
+            }
+            return;
+        }
+
         // Type each character
         for (int i = 0; i < text.length(); i++) {
             char ch = text.charAt(i);
@@ -967,6 +915,93 @@ public class InputProcessor {
     }
 
     private void executeMnemonicToken(String token) {
+        if (isNvtMode()) {
+            try {
+                switch (token) {
+                    case "enter":
+                    case "return":
+                        fsm.sendNVTString("\r\n");
+                        break;
+                    case "clear":
+                        fsm.sendNVTChar('\u000C');
+                        break;
+                    case "tab":
+                        fsm.sendNVTChar('\t');
+                        break;
+                    case "backtab":
+                    case "btab":
+                        fsm.sendNVTString("\u001B[Z");
+                        break;
+                    case "newline":
+                    case "nl":
+                        fsm.sendNVTString("\r\n");
+                        break;
+                    case "home":
+                        fsm.sendNVTString("\u001B[H");
+                        break;
+                    case "end":
+                        fsm.sendNVTString("\u001B[F");
+                        break;
+                    case "up":
+                    case "curup":
+                        fsm.sendNVTString("\u001B[A");
+                        break;
+                    case "down":
+                    case "curdown":
+                        fsm.sendNVTString("\u001B[B");
+                        break;
+                    case "left":
+                    case "curleft":
+                        fsm.sendNVTString("\u001B[D");
+                        break;
+                    case "right":
+                    case "curright":
+                        fsm.sendNVTString("\u001B[C");
+                        break;
+                    case "pageup":
+                    case "pgup":
+                        fsm.sendNVTString("\u001B[5~");
+                        break;
+                    case "pagedown":
+                    case "pgdn":
+                        fsm.sendNVTString("\u001B[6~");
+                        break;
+                    case "delete":
+                    case "del":
+                        fsm.sendNVTString("\u001B[3~");
+                        break;
+                    case "backspace":
+                    case "bs":
+                        fsm.sendNVTChar('\b');
+                        break;
+                    case "attn":
+                    case "break":
+                        fsm.sendNVTChar('\u0003');
+                        break;
+                    case "sysreq":
+                    case "escape":
+                    case "esc":
+                        fsm.sendNVTChar('\u001B');
+                        break;
+                    case "reset":
+                        setKeyboardLocked(false);
+                        break;
+                    default:
+                        if (token.startsWith("pf") || token.startsWith("f")) {
+                            try {
+                                String numStr = token.startsWith("pf") ? token.substring(2) : token.substring(1);
+                                int fn = Integer.parseInt(numStr);
+                                sendNvtFunctionKey(fn);
+                            } catch (NumberFormatException ignored) {}
+                        }
+                        break;
+                }
+            } catch (IOException e) {
+                log.warning("Failed to send NVT mnemonic token: " + e.getMessage());
+            }
+            return;
+        }
+
         switch (token) {
             case "enter":
             case "return":
@@ -1068,6 +1103,24 @@ public class InputProcessor {
         }
     }
 
+    private void sendNvtFunctionKey(int fn) throws IOException {
+        switch (fn) {
+            case 1: fsm.sendNVTString("\u001BOP"); break;
+            case 2: fsm.sendNVTString("\u001BOQ"); break;
+            case 3: fsm.sendNVTString("\u001BOR"); break;
+            case 4: fsm.sendNVTString("\u001BOS"); break;
+            case 5: fsm.sendNVTString("\u001B[15~"); break;
+            case 6: fsm.sendNVTString("\u001B[17~"); break;
+            case 7: fsm.sendNVTString("\u001B[18~"); break;
+            case 8: fsm.sendNVTString("\u001B[19~"); break;
+            case 9: fsm.sendNVTString("\u001B[20~"); break;
+            case 10: fsm.sendNVTString("\u001B[21~"); break;
+            case 11: fsm.sendNVTString("\u001B[23~"); break;
+            case 12: fsm.sendNVTString("\u001B[24~"); break;
+            default: break;
+        }
+    }
+
     /**
      * Jump cursor to next or previous word boundary.
      */
diff --git a/lib3270j/src/main/java/haus/nightmare/lib3270j/listener/SCSInboundListener.java b/lib3270j/src/main/java/haus/nightmare/lib3270j/listener/SCSInboundListener.java
new file mode 100644
index 0000000..07cc255
--- /dev/null
+++ b/lib3270j/src/main/java/haus/nightmare/lib3270j/listener/SCSInboundListener.java
@@ -0,0 +1,17 @@
+package haus.nightmare.lib3270j.listener;
+
+/**
+ * Listener interface for receiving inbound SCS (SNA Character String) data streams
+ * transmitted by the host in TN3270E mode (Data Type DT_SCS_DATA = 0x01).
+ */
+public interface SCSInboundListener {
+
+    /**
+     * Called when an inbound SCS record is received from the host.
+     *
+     * @param data Raw SCS record payload bytes
+     * @param offset Start offset within buffer
+     * @param length Number of bytes in record
+     */
+    void onSCSDataReceived(byte[] data, int offset, int length);
+}
diff --git a/lib3270j/src/main/java/haus/nightmare/lib3270j/nvt/NvtProcessor.java b/lib3270j/src/main/java/haus/nightmare/lib3270j/nvt/NvtProcessor.java
index 1dad215..c0465cd 100644
--- a/lib3270j/src/main/java/haus/nightmare/lib3270j/nvt/NvtProcessor.java
+++ b/lib3270j/src/main/java/haus/nightmare/lib3270j/nvt/NvtProcessor.java
@@ -9,7 +9,7 @@ import static haus.nightmare.lib3270j.protocol.DS3270Constants.*;
 import java.io.ByteArrayOutputStream;
 import java.io.IOException;
 import java.nio.charset.StandardCharsets;
-import java.util.ArrayList;
+import java.util.Arrays;
 import java.util.List;
 import java.util.concurrent.CopyOnWriteArrayList;
 import java.util.logging.Logger;
@@ -17,7 +17,7 @@ import java.util.logging.Logger;
 /**
  * Network Virtual Terminal (NVT) processor.
  * Handles ASCII / ANSI VT100 character stream processing, cursor positioning,
- * escape sequence decoding, and NVT character/string transmission.
+ * escape sequence decoding, terminal capability reports, and NVT transmission.
  */
 public class NvtProcessor {
 
@@ -28,9 +28,10 @@ public class NvtProcessor {
     private final List<ScreenUpdateListener> screenListeners = new CopyOnWriteArrayList<>();
 
     // Escape sequence parser states
-    private static final int STATE_NORMAL = 0;
-    private static final int STATE_ESC    = 1;
-    private static final int STATE_CSI    = 2;
+    private static final int STATE_NORMAL   = 0;
+    private static final int STATE_ESC      = 1;
+    private static final int STATE_CSI      = 2;
+    private static final int STATE_CHARSET  = 3;
 
     private int parseState = STATE_NORMAL;
     private final ByteArrayOutputStream escBuffer = new ByteArrayOutputStream();
@@ -47,6 +48,21 @@ public class NvtProcessor {
     private int savedCursorRow = 0;
     private int savedCursorCol = 0;
 
+    // Scrolling margins (0-indexed, inclusive)
+    private int scrollTop = 0;
+    private int scrollBottom = -1; // -1 means default (rows - 1)
+
+    // Tab stops
+    private boolean[] tabStops;
+
+    // Cursor visibility
+    private boolean cursorVisible = true;
+
+    // Line drawing mode
+    private boolean lineDrawingG0 = false;
+    private boolean lineDrawingG1 = false;
+    private boolean activeCharsetG1 = false;
+
     @FunctionalInterface
     public interface OutputSender {
         void sendRaw(byte[] data) throws IOException;
@@ -55,6 +71,15 @@ public class NvtProcessor {
     public NvtProcessor(ScreenBuffer screenBuffer, EbcdicTranslator translator) {
         this.screenBuffer = screenBuffer;
         this.translator = translator;
+        initTabStops();
+    }
+
+    private void initTabStops() {
+        int cols = screenBuffer.getCols();
+        tabStops = new boolean[cols];
+        for (int i = 0; i < cols; i++) {
+            tabStops[i] = (i % 8 == 0);
+        }
     }
 
     public void setOutputSender(OutputSender outputSender) {
@@ -65,6 +90,14 @@ public class NvtProcessor {
         screenListeners.add(l);
     }
 
+    public void removeScreenUpdateListener(ScreenUpdateListener l) {
+        screenListeners.remove(l);
+    }
+
+    public boolean isCursorVisible() {
+        return cursorVisible;
+    }
+
     /**
      * Process incoming ASCII NVT data bytes.
      */
@@ -73,6 +106,12 @@ public class NvtProcessor {
 
         int rows = screenBuffer.getRows();
         int cols = screenBuffer.getCols();
+        if (tabStops == null || tabStops.length != cols) {
+            initTabStops();
+        }
+        int effectiveScrollBottom = (scrollBottom >= 0 && scrollBottom < rows) ? scrollBottom : rows - 1;
+        int effectiveScrollTop = Math.max(0, Math.min(scrollTop, effectiveScrollBottom));
+
         int size = rows * cols;
         int curAddr = screenBuffer.getCursorAddress();
 
@@ -90,27 +129,60 @@ public class NvtProcessor {
                 } else if (b == 0x0A) { // LF
                     int r = curAddr / cols;
                     int c = curAddr % cols;
-                    r++;
-                    if (r >= rows) {
-                        scrollUp();
-                        r = rows - 1;
+                    if (r == effectiveScrollBottom) {
+                        scrollUpRegion(effectiveScrollTop, effectiveScrollBottom);
+                    } else if (r < rows - 1) {
+                        r++;
                     }
                     curAddr = r * cols + c;
-                } else if (b == 0x08 || b == 0x7F) { // BS or DEL
+                } else if (b == 0x08) { // BS
                     int c = curAddr % cols;
                     if (c > 0) {
                         curAddr--;
                     }
+                } else if (b == 0x7F) { // DEL
+                    // Ignore or backspace per NVT convention
                 } else if (b == 0x09) { // TAB
+                    int r = curAddr / cols;
                     int c = curAddr % cols;
-                    int nextTab = ((c / 8) + 1) * 8;
-                    if (nextTab >= cols) nextTab = cols - 1;
-                    curAddr = (curAddr / cols) * cols + nextTab;
+                    int nextTab = cols - 1;
+                    for (int tc = c + 1; tc < cols; tc++) {
+                        if (tc < tabStops.length && tabStops[tc]) {
+                            nextTab = tc;
+                            break;
+                        }
+                    }
+                    curAddr = r * cols + nextTab;
                 } else if (b == 0x0C) { // FF
                     screenBuffer.clear();
                     curAddr = 0;
-                } else if (b >= 0x20 && b < 0xFF) { // Printable ASCII
+                } else if (b == 0x07) { // BEL
+                    for (ScreenUpdateListener l : screenListeners) {
+                        l.onSoundAlarm();
+                    }
+                } else if (b == 0x0E) { // SO (Select G1 charset)
+                    activeCharsetG1 = true;
+                } else if (b == 0x0F) { // SI (Select G0 charset)
+                    activeCharsetG1 = false;
+                } else if (b >= 0x20 && b <= 0xFF) { // Printable character
                     char ch = (char) b;
+                    if (activeCharsetG1 ? lineDrawingG1 : lineDrawingG0) {
+                        ch = mapVt100SpecialGraphics(ch);
+                    }
+
+                    int r = curAddr / cols;
+                    int c = curAddr % cols;
+
+                    if (c >= cols) {
+                        c = 0;
+                        if (r == effectiveScrollBottom) {
+                            scrollUpRegion(effectiveScrollTop, effectiveScrollBottom);
+                        } else if (r < rows - 1) {
+                            r++;
+                        }
+                        curAddr = r * cols + c;
+                    }
+
                     int ebc = translator.unicodeToEbcdic(ch);
                     ExtendedAttribute cell = screenBuffer.getCell(curAddr);
                     cell.clear();
@@ -120,37 +192,98 @@ public class NvtProcessor {
                     cell.bg = currentBg;
                     cell.gr = currentGr;
 
-                    curAddr++;
-                    if (curAddr >= size) {
-                        scrollUp();
-                        curAddr = (rows - 1) * cols;
+                    c++;
+                    if (c >= cols) {
+                        if (r < rows - 1) {
+                            if (r == effectiveScrollBottom) {
+                                scrollUpRegion(effectiveScrollTop, effectiveScrollBottom);
+                                c = 0;
+                            } else {
+                                r++;
+                                c = 0;
+                            }
+                        } else {
+                            scrollUpRegion(effectiveScrollTop, effectiveScrollBottom);
+                            c = 0;
+                        }
                     }
+                    curAddr = r * cols + c;
                 }
             } else if (parseState == STATE_ESC) {
                 escBuffer.write(b);
                 if (b == '[') {
                     parseState = STATE_CSI;
-                } else if (b == '7') { // Save cursor
+                } else if (b == '(' || b == ')') {
+                    parseState = STATE_CHARSET;
+                } else if (b == '7') { // DECSC - Save cursor
                     savedCursorRow = curAddr / cols;
                     savedCursorCol = curAddr % cols;
                     parseState = STATE_NORMAL;
-                } else if (b == '8') { // Restore cursor
+                } else if (b == '8') { // DECRC - Restore cursor
                     curAddr = Math.min(rows - 1, savedCursorRow) * cols + Math.min(cols - 1, savedCursorCol);
                     parseState = STATE_NORMAL;
+                } else if (b == 'D') { // IND - Index (down 1 line)
+                    int r = curAddr / cols;
+                    int c = curAddr % cols;
+                    if (r == effectiveScrollBottom) {
+                        scrollUpRegion(effectiveScrollTop, effectiveScrollBottom);
+                    } else if (r < rows - 1) {
+                        r++;
+                    }
+                    curAddr = r * cols + c;
+                    parseState = STATE_NORMAL;
+                } else if (b == 'M') { // RI - Reverse Index (up 1 line)
+                    int r = curAddr / cols;
+                    int c = curAddr % cols;
+                    if (r == effectiveScrollTop) {
+                        scrollDownRegion(effectiveScrollTop, effectiveScrollBottom);
+                    } else if (r > 0) {
+                        r--;
+                    }
+                    curAddr = r * cols + c;
+                    parseState = STATE_NORMAL;
+                } else if (b == 'E') { // NEL - Next Line (CR + LF)
+                    int r = curAddr / cols;
+                    if (r == effectiveScrollBottom) {
+                        scrollUpRegion(effectiveScrollTop, effectiveScrollBottom);
+                    } else if (r < rows - 1) {
+                        r++;
+                    }
+                    curAddr = r * cols;
+                    parseState = STATE_NORMAL;
+                } else if (b == 'H') { // HTS - Horizontal Tab Set
+                    int c = curAddr % cols;
+                    if (c < tabStops.length) {
+                        tabStops[c] = true;
+                    }
+                    parseState = STATE_NORMAL;
                 } else if (b == 'c') { // RIS - Reset to Initial State
                     screenBuffer.clear();
                     curAddr = 0;
                     currentFg = 0;
                     currentBg = 0;
                     currentGr = 0;
+                    scrollTop = 0;
+                    scrollBottom = rows - 1;
+                    cursorVisible = true;
+                    initTabStops();
                     parseState = STATE_NORMAL;
                 } else {
-                    // Unknown 2-byte escape, finish
+                    // Unknown 2-byte escape, return to normal
                     parseState = STATE_NORMAL;
                 }
+            } else if (parseState == STATE_CHARSET) {
+                byte[] seq = escBuffer.toByteArray();
+                if (seq.length >= 2) {
+                    boolean isG1 = (seq[1] == ')');
+                    boolean isLineDraw = (b == '0');
+                    if (isG1) lineDrawingG1 = isLineDraw;
+                    else lineDrawingG0 = isLineDraw;
+                }
+                parseState = STATE_NORMAL;
             } else if (parseState == STATE_CSI) {
                 escBuffer.write(b);
-                // CSI parameter/intermediate bytes: 0x20..0x3F, final bytes: 0x40..0x7E
+                // CSI final bytes are in the range 0x40..0x7E
                 if (b >= 0x40 && b <= 0x7E) {
                     byte[] seq = escBuffer.toByteArray();
                     curAddr = processAnsiEscapeSequence(seq, curAddr, rows, cols);
@@ -159,7 +292,7 @@ public class NvtProcessor {
             }
         }
 
-        screenBuffer.setCursorAddress(curAddr);
+        screenBuffer.setCursorAddress(Math.max(0, Math.min(size - 1, curAddr)));
         screenBuffer.markAllChanged();
         screenBuffer.updateDisplaySnapshot();
         notifyScreenUpdated();
@@ -175,6 +308,9 @@ public class NvtProcessor {
         String paramStr = new String(seq, 2, seq.length - 3, StandardCharsets.US_ASCII);
         String[] params = paramStr.split(";");
 
+        int effectiveScrollBottom = (scrollBottom >= 0 && scrollBottom < rows) ? scrollBottom : rows - 1;
+        int effectiveScrollTop = Math.max(0, Math.min(scrollTop, effectiveScrollBottom));
+
         int r = curAddr / cols;
         int c = curAddr % cols;
 
@@ -212,6 +348,31 @@ public class NvtProcessor {
                 c = Math.max(0, c - count);
                 return r * cols + c;
             }
+            case 'E': // CNL - Cursor Next Line
+            {
+                int count = parseParam(params, 0, 1);
+                r = Math.min(rows - 1, r + count);
+                return r * cols; // column 0
+            }
+            case 'F': // CPL - Cursor Previous Line
+            {
+                int count = parseParam(params, 0, 1);
+                r = Math.max(0, r - count);
+                return r * cols; // column 0
+            }
+            case 'G': // CHA - Cursor Horizontal Absolute
+            case '`': // HPA - Horizontal Position Absolute
+            {
+                int p = parseParam(params, 0, 1) - 1;
+                c = Math.max(0, Math.min(cols - 1, p));
+                return r * cols + c;
+            }
+            case 'd': // VPA - Vertical Position Absolute
+            {
+                int p = parseParam(params, 0, 1) - 1;
+                r = Math.max(0, Math.min(rows - 1, p));
+                return r * cols + c;
+            }
             case 'J': // ED - Erase in Display
             {
                 int mode = parseParam(params, 0, 0);
@@ -239,6 +400,84 @@ public class NvtProcessor {
                 }
                 return curAddr;
             }
+            case 'L': // IL - Insert Line
+            {
+                int count = parseParam(params, 0, 1);
+                for (int n = 0; n < count; n++) {
+                    scrollDownRegion(r, effectiveScrollBottom);
+                }
+                return r * cols;
+            }
+            case 'M': // DL - Delete Line
+            {
+                int count = parseParam(params, 0, 1);
+                for (int n = 0; n < count; n++) {
+                    scrollUpRegion(r, effectiveScrollBottom);
+                }
+                return r * cols;
+            }
+            case '@': // ICH - Insert Character
+            {
+                int count = parseParam(params, 0, 1);
+                int lineStart = r * cols;
+                for (int col = cols - 1; col >= c + count; col--) {
+                    screenBuffer.getCell(lineStart + col).copyFrom(screenBuffer.getCell(lineStart + col - count));
+                }
+                for (int col = c; col < Math.min(cols, c + count); col++) {
+                    clearCell(lineStart + col);
+                }
+                return curAddr;
+            }
+            case 'P': // DCH - Delete Character
+            {
+                int count = parseParam(params, 0, 1);
+                int lineStart = r * cols;
+                for (int col = c; col < cols - count; col++) {
+                    screenBuffer.getCell(lineStart + col).copyFrom(screenBuffer.getCell(lineStart + col + count));
+                }
+                for (int col = cols - count; col < cols; col++) {
+                    clearCell(lineStart + col);
+                }
+                return curAddr;
+            }
+            case 'X': // ECH - Erase Character
+            {
+                int count = parseParam(params, 0, 1);
+                int end = Math.min((r + 1) * cols, curAddr + count);
+                for (int i = curAddr; i < end; i++) {
+                    clearCell(i);
+                }
+                return curAddr;
+            }
+            case 'S': // SU - Scroll Up
+            {
+                int count = parseParam(params, 0, 1);
+                for (int n = 0; n < count; n++) {
+                    scrollUpRegion(effectiveScrollTop, effectiveScrollBottom);
+                }
+                return curAddr;
+            }
+            case 'T': // SD - Scroll Down
+            {
+                int count = parseParam(params, 0, 1);
+                for (int n = 0; n < count; n++) {
+                    scrollDownRegion(effectiveScrollTop, effectiveScrollBottom);
+                }
+                return curAddr;
+            }
+            case 'r': // DECSTBM - Set Top and Bottom Margins (Scrolling Region)
+            {
+                int top = parseParam(params, 0, 1) - 1;
+                int bottom = parseParam(params, 1, rows) - 1;
+                if (top >= 0 && bottom < rows && top < bottom) {
+                    scrollTop = top;
+                    scrollBottom = bottom;
+                } else {
+                    scrollTop = 0;
+                    scrollBottom = rows - 1;
+                }
+                return 0; // Move cursor to home
+            }
             case 'm': // SGR - Select Graphic Rendition
             {
                 if (params.length == 0 || (params.length == 1 && params[0].isEmpty())) {
@@ -256,6 +495,57 @@ public class NvtProcessor {
                 }
                 return curAddr;
             }
+            case 'n': // DSR - Device Status Report
+            {
+                int code = parseParam(params, 0, 0);
+                if (code == 6) { // Cursor position request
+                    // Reply: ESC [ <row> ; <col> R (1-indexed)
+                    String response = String.format("\u001B[%d;%dR", r + 1, c + 1);
+                    sendResponseString(response);
+                } else if (code == 5) { // Status report request
+                    sendResponseString("\u001B[0n"); // OK
+                }
+                return curAddr;
+            }
+            case 'c': // DA - Device Attributes
+            {
+                int code = parseParam(params, 0, 0);
+                if (code == 0) {
+                    // Identify as standard VT100 with Advanced Video Option
+                    sendResponseString("\u001B[?1;2c");
+                }
+                return curAddr;
+            }
+            case 'g': // TBC - Tab Clear
+            {
+                int mode = parseParam(params, 0, 0);
+                if (mode == 0) {
+                    if (c < tabStops.length) tabStops[c] = false;
+                } else if (mode == 3) {
+                    Arrays.fill(tabStops, false);
+                }
+                return curAddr;
+            }
+            case 'h': // Set Mode / Private Mode
+            {
+                if (paramStr.startsWith("?")) {
+                    String sub = paramStr.substring(1).trim();
+                    if ("25".equals(sub)) {
+                        cursorVisible = true;
+                    }
+                }
+                return curAddr;
+            }
+            case 'l': // Reset Mode / Private Mode
+            {
+                if (paramStr.startsWith("?")) {
+                    String sub = paramStr.substring(1).trim();
+                    if ("25".equals(sub)) {
+                        cursorVisible = false;
+                    }
+                }
+                return curAddr;
+            }
             case 's': // Save cursor
                 savedCursorRow = r;
                 savedCursorCol = c;
@@ -269,10 +559,22 @@ public class NvtProcessor {
         }
     }
 
+    private void sendResponseString(String s) {
+        if (outputSender != null) {
+            try {
+                outputSender.sendRaw(s.getBytes(StandardCharsets.US_ASCII));
+            } catch (IOException e) {
+                log.warning("Failed to send ANSI response: " + e.getMessage());
+            }
+        }
+    }
+
     private int parseParam(String[] params, int idx, int defaultVal) {
         if (params != null && idx < params.length && !params[idx].trim().isEmpty()) {
             try {
-                return Integer.parseInt(params[idx].trim());
+                String val = params[idx].trim();
+                if (val.startsWith("?")) val = val.substring(1);
+                return Integer.parseInt(val);
             } catch (NumberFormatException ignored) {}
         }
         return defaultVal;
@@ -281,27 +583,73 @@ public class NvtProcessor {
     private void clearCell(int addr) {
         ExtendedAttribute cell = screenBuffer.getCell(addr);
         cell.clear();
-        cell.ec = 0;
+        cell.ec = (byte) 0x40; // EBCDIC space
         cell.ucs4 = ' ';
+        cell.fg = 0;
+        cell.bg = 0;
+        cell.gr = 0;
     }
 
-    private void scrollUp() {
+    private void scrollUpRegion(int top, int bottom) {
         int rows = screenBuffer.getRows();
         int cols = screenBuffer.getCols();
-        for (int r = 0; r < rows - 1; r++) {
+        top = Math.max(0, Math.min(rows - 1, top));
+        bottom = Math.max(top, Math.min(rows - 1, bottom));
+
+        for (int r = top; r < bottom; r++) {
             for (int c = 0; c < cols; c++) {
                 int dst = r * cols + c;
                 int src = (r + 1) * cols + c;
                 screenBuffer.getCell(dst).copyFrom(screenBuffer.getCell(src));
             }
         }
-        // Clear last line
-        int lastRowStart = (rows - 1) * cols;
+        int lastRowStart = bottom * cols;
         for (int c = 0; c < cols; c++) {
             clearCell(lastRowStart + c);
         }
     }
 
+    private void scrollDownRegion(int top, int bottom) {
+        int rows = screenBuffer.getRows();
+        int cols = screenBuffer.getCols();
+        top = Math.max(0, Math.min(rows - 1, top));
+        bottom = Math.max(top, Math.min(rows - 1, bottom));
+
+        for (int r = bottom; r > top; r--) {
+            for (int c = 0; c < cols; c++) {
+                int dst = r * cols + c;
+                int src = (r - 1) * cols + c;
+                screenBuffer.getCell(dst).copyFrom(screenBuffer.getCell(src));
+            }
+        }
+        int topRowStart = top * cols;
+        for (int c = 0; c < cols; c++) {
+            clearCell(topRowStart + c);
+        }
+    }
+
+    private char mapVt100SpecialGraphics(char c) {
+        switch (c) {
+            case 'j': return '┘';
+            case 'k': return '┐';
+            case 'l': return '┌';
+            case 'm': return '└';
+            case 'n': return '┼';
+            case 'q': return '─';
+            case 't': return '├';
+            case 'u': return '┤';
+            case 'v': return '┴';
+            case 'w': return '┬';
+            case 'x': return '│';
+            case '`': return '◆';
+            case 'a': return '▒';
+            case 'f': return '°';
+            case 'g': return '±';
+            case '~': return '•';
+            default:  return c;
+        }
+    }
+
     private void applySgr(int code) {
         switch (code) {
             case 0: // Reset
diff --git a/lib3270j/src/main/java/haus/nightmare/lib3270j/protocol/TelnetConstants.java b/lib3270j/src/main/java/haus/nightmare/lib3270j/protocol/TelnetConstants.java
index 3c1f896..6f7828d 100644
--- a/lib3270j/src/main/java/haus/nightmare/lib3270j/protocol/TelnetConstants.java
+++ b/lib3270j/src/main/java/haus/nightmare/lib3270j/protocol/TelnetConstants.java
@@ -115,4 +115,23 @@ public final class TelnetConstants {
             default:    return "CMD-" + cmd;
         }
     }
+    public static String qualifierName(int qual) {
+        switch (qual) {
+            case TELQUAL_IS:   return "IS";
+            case TELQUAL_SEND: return "SEND";
+            case TELQUAL_INFO: return "INFO";
+            default:           return "QUAL-" + qual;
+        }
+    }
+
+    /** NEW-ENVIRON object name lookup. */
+    public static String environObjectName(int obj) {
+        switch (obj) {
+            case TELOBJ_VAR:     return "VAR";
+            case TELOBJ_VALUE:   return "VALUE";
+            case TELOBJ_ESC:     return "ESC";
+            case TELOBJ_USERVAR: return "USERVAR";
+            default:             return "OBJ-" + obj;
+        }
+    }
 }
diff --git a/lib3270j/src/main/java/haus/nightmare/lib3270j/telnet/TelnetConnection.java b/lib3270j/src/main/java/haus/nightmare/lib3270j/telnet/TelnetConnection.java
index b43f56d..faa2e8e 100644
--- a/lib3270j/src/main/java/haus/nightmare/lib3270j/telnet/TelnetConnection.java
+++ b/lib3270j/src/main/java/haus/nightmare/lib3270j/telnet/TelnetConnection.java
@@ -40,44 +40,71 @@ public class TelnetConnection {
     }
 
     /**
-     * Connect to the host. Blocks until connection is established or fails.
+     * Connect to the host (optionally through a proxy). Blocks until connection is established or fails.
      */
     public void connect() throws IOException {
+        ConnectionConfig.ProxyType proxyType = config.getProxyType();
+        boolean hasProxy = proxyType != null && proxyType != ConnectionConfig.ProxyType.NONE &&
+                config.getProxyHost() != null && !config.getProxyHost().trim().isEmpty();
+
+        String connectHost = hasProxy ? config.getProxyHost().trim() : config.getHost();
+        int connectPort = hasProxy ? (config.getProxyPort() > 0 ? config.getProxyPort() : (proxyType == ConnectionConfig.ProxyType.HTTP ? 8080 : 1080)) : config.getPort();
+
+        log.info("Connecting TCP socket to " + connectHost + ":" + connectPort +
+                (hasProxy ? " (via " + proxyType + " proxy for " + config.getHost() + ":" + config.getPort() + ")" : "") +
+                (config.isUseTls() ? " with TLS" : ""));
+
+        Socket rawSocket = new Socket();
+        rawSocket.setKeepAlive(config.isSoKeepAlive());
+        rawSocket.setOOBInline(true);
+        rawSocket.setTcpNoDelay(config.isTcpNoDelay());
+        if (config.getSoTimeoutMs() > 0) {
+            rawSocket.setSoTimeout(config.getSoTimeoutMs());
+        }
+        rawSocket.connect(new InetSocketAddress(connectHost, connectPort), config.getConnectTimeoutMs());
+
+        // Perform proxy handshake if configured
+        if (hasProxy) {
+            switch (proxyType) {
+                case HTTP:
+                    establishHttpProxy(rawSocket, config.getHost(), config.getPort(), config.getProxyUsername(), config.getProxyPassword());
+                    break;
+                case SOCKS4:
+                    establishSocks4Proxy(rawSocket, config.getHost(), config.getPort(), config.getProxyUsername());
+                    break;
+                case SOCKS5:
+                    establishSocks5Proxy(rawSocket, config.getHost(), config.getPort(), config.getProxyUsername(), config.getProxyPassword());
+                    break;
+                default:
+                    break;
+            }
+        }
+
         if (config.isUseTls()) {
-            log.info("Connecting with TLS to " + config.getHost() + ":" + config.getPort() +
+            log.info("Performing TLS handshake with " + config.getHost() + ":" + config.getPort() +
                     " (verifyCert=" + config.isTlsVerifyCert() + ")");
             try {
                 javax.net.ssl.SSLContext sslContext = haus.nightmare.lib3270j.tls.TlsTrustManager.createSSLContext(config);
                 javax.net.ssl.SSLSocketFactory ssf = sslContext.getSocketFactory();
-                javax.net.ssl.SSLSocket sslSocket = (javax.net.ssl.SSLSocket) ssf.createSocket();
+                javax.net.ssl.SSLSocket sslSocket = (javax.net.ssl.SSLSocket) ssf.createSocket(
+                        rawSocket, config.getHost(), config.getPort(), true);
                 sslSocket.setKeepAlive(config.isSoKeepAlive());
                 sslSocket.setTcpNoDelay(config.isTcpNoDelay());
                 if (config.getSoTimeoutMs() > 0) {
                     sslSocket.setSoTimeout(config.getSoTimeoutMs());
                 }
-                sslSocket.connect(new InetSocketAddress(config.getHost(), config.getPort()),
-                               config.getConnectTimeoutMs());
                 sslSocket.startHandshake();
                 socket = sslSocket;
                 sslSession = sslSocket.getSession();
                 log.info("TLS session active: protocol=" + sslSession.getProtocol() +
-                         " cipher=" + sslSession.getCipherSuite());
+                        " cipher=" + sslSession.getCipherSuite());
             } catch (IOException e) {
                 throw e;
             } catch (Exception e) {
                 throw new IOException("TLS setup failure: " + e.getMessage(), e);
             }
         } else {
-            log.info("Connecting to " + config.getHost() + ":" + config.getPort());
-            socket = new Socket();
-            socket.setKeepAlive(config.isSoKeepAlive());
-            socket.setOOBInline(true);
-            socket.setTcpNoDelay(config.isTcpNoDelay());
-            if (config.getSoTimeoutMs() > 0) {
-                socket.setSoTimeout(config.getSoTimeoutMs());
-            }
-            socket.connect(new InetSocketAddress(config.getHost(), config.getPort()),
-                           config.getConnectTimeoutMs());
+            socket = rawSocket;
         }
 
         inputStream = new BufferedInputStream(socket.getInputStream(), READ_BUFFER_SIZE);
@@ -91,6 +118,235 @@ public class TelnetConnection {
         readerThread.start();
     }
 
+    /**
+     * Dynamically elevate active socket to TLS in-band (STARTTLS / Option 46).
+     */
+    public synchronized void upgradeToTls() throws IOException {
+        if (socket == null || !socket.isConnected() || socket.isClosed()) {
+            throw new IOException("Cannot upgrade disconnected socket to TLS");
+        }
+        log.info("Elevating active connection to TLS via STARTTLS");
+        try {
+            javax.net.ssl.SSLContext sslContext = haus.nightmare.lib3270j.tls.TlsTrustManager.createSSLContext(config);
+            javax.net.ssl.SSLSocketFactory ssf = sslContext.getSocketFactory();
+            javax.net.ssl.SSLSocket sslSocket = (javax.net.ssl.SSLSocket) ssf.createSocket(
+                    socket, config.getHost(), config.getPort(), true);
+            sslSocket.setKeepAlive(config.isSoKeepAlive());
+            sslSocket.setTcpNoDelay(config.isTcpNoDelay());
+            if (config.getSoTimeoutMs() > 0) {
+                sslSocket.setSoTimeout(config.getSoTimeoutMs());
+            }
+            sslSocket.startHandshake();
+            this.socket = sslSocket;
+            this.sslSession = sslSocket.getSession();
+            this.inputStream = new BufferedInputStream(sslSocket.getInputStream(), READ_BUFFER_SIZE);
+            this.outputStream = new BufferedOutputStream(sslSocket.getOutputStream());
+            log.info("STARTTLS session active: protocol=" + sslSession.getProtocol() +
+                    " cipher=" + sslSession.getCipherSuite());
+        } catch (IOException e) {
+            throw e;
+        } catch (Exception e) {
+            throw new IOException("STARTTLS setup failure: " + e.getMessage(), e);
+        }
+    }
+
+    private void establishHttpProxy(Socket s, String targetHost, int targetPort, String user, String pass) throws IOException {
+        OutputStream out = s.getOutputStream();
+        InputStream in = s.getInputStream();
+
+        StringBuilder req = new StringBuilder();
+        req.append("CONNECT ").append(targetHost).append(":").append(targetPort).append(" HTTP/1.1\r\n");
+        req.append("Host: ").append(targetHost).append(":").append(targetPort).append("\r\n");
+        if (user != null && !user.isEmpty()) {
+            String auth = user + ":" + (pass != null ? pass : "");
+            String encoded = java.util.Base64.getEncoder().encodeToString(auth.getBytes(java.nio.charset.StandardCharsets.UTF_8));
+            req.append("Proxy-Authorization: Basic ").append(encoded).append("\r\n");
+        }
+        req.append("Proxy-Connection: Keep-Alive\r\n\r\n");
+        out.write(req.toString().getBytes(java.nio.charset.StandardCharsets.US_ASCII));
+        out.flush();
+
+        // Read HTTP status line
+        ByteArrayOutputStream lineBuf = new ByteArrayOutputStream();
+        int b;
+        while ((b = in.read()) != -1) {
+            if (b == '\n') break;
+            if (b != '\r') lineBuf.write(b);
+        }
+        String statusLine = new String(lineBuf.toByteArray(), java.nio.charset.StandardCharsets.US_ASCII);
+        if (!statusLine.contains(" 200")) {
+            throw new IOException("HTTP proxy connection failed: " + statusLine);
+        }
+
+        // Consume remaining response headers until empty line
+        while (true) {
+            lineBuf.reset();
+            while ((b = in.read()) != -1) {
+                if (b == '\n') break;
+                if (b != '\r') lineBuf.write(b);
+            }
+            if (lineBuf.size() == 0) break; // empty line terminates headers
+        }
+        log.info("HTTP proxy tunnel established to " + targetHost + ":" + targetPort);
+    }
+
+    private void establishSocks4Proxy(Socket s, String targetHost, int targetPort, String user) throws IOException {
+        OutputStream out = s.getOutputStream();
+        InputStream in = s.getInputStream();
+
+        byte[] ip = new byte[4];
+        boolean isSocks4a = false;
+        try {
+            InetAddress addr = InetAddress.getByName(targetHost);
+            if (addr instanceof Inet4Address) {
+                ip = addr.getAddress();
+            } else {
+                isSocks4a = true;
+                ip = new byte[] { 0, 0, 0, 1 };
+            }
+        } catch (Exception e) {
+            isSocks4a = true;
+            ip = new byte[] { 0, 0, 0, 1 };
+        }
+
+        ByteArrayOutputStream req = new ByteArrayOutputStream();
+        req.write(0x04); // SOCKS version 4
+        req.write(0x01); // CONNECT command
+        req.write((targetPort >> 8) & 0xFF);
+        req.write(targetPort & 0xFF);
+        req.write(ip);
+        if (user != null && !user.isEmpty()) {
+            req.write(user.getBytes(java.nio.charset.StandardCharsets.ISO_8859_1));
+        }
+        req.write(0x00); // Null terminator for userid
+        if (isSocks4a) {
+            req.write(targetHost.getBytes(java.nio.charset.StandardCharsets.ISO_8859_1));
+            req.write(0x00); // Null terminator for domain name
+        }
+
+        out.write(req.toByteArray());
+        out.flush();
+
+        byte[] resp = new byte[8];
+        int read = 0;
+        while (read < 8) {
+            int n = in.read(resp, read, 8 - read);
+            if (n < 0) throw new IOException("Unexpected EOF reading SOCKS4 response");
+            read += n;
+        }
+
+        int status = resp[1] & 0xFF;
+        if (status != 0x5A) {
+            throw new IOException("SOCKS4 proxy request rejected, status=0x" + Integer.toHexString(status));
+        }
+        log.info("SOCKS4 proxy tunnel established to " + targetHost + ":" + targetPort);
+    }
+
+    private void establishSocks5Proxy(Socket s, String targetHost, int targetPort, String user, String pass) throws IOException {
+        OutputStream out = s.getOutputStream();
+        InputStream in = s.getInputStream();
+
+        boolean hasAuth = user != null && !user.isEmpty();
+        if (hasAuth) {
+            out.write(new byte[] { 0x05, 0x02, 0x00, 0x02 }); // SOCKS5, 2 methods: NO_AUTH(0x00), USER_PASS(0x02)
+        } else {
+            out.write(new byte[] { 0x05, 0x01, 0x00 }); // SOCKS5, 1 method: NO_AUTH(0x00)
+        }
+        out.flush();
+
+        byte[] methodResp = new byte[2];
+        readFully(in, methodResp);
+        if ((methodResp[0] & 0xFF) != 0x05) {
+            throw new IOException("Invalid SOCKS5 version response: " + (methodResp[0] & 0xFF));
+        }
+
+        int authMethod = methodResp[1] & 0xFF;
+        if (authMethod == 0x02) {
+            // RFC 1929 Username/Password Authentication
+            byte[] uBytes = user.getBytes(java.nio.charset.StandardCharsets.UTF_8);
+            byte[] pBytes = (pass != null ? pass : "").getBytes(java.nio.charset.StandardCharsets.UTF_8);
+            ByteArrayOutputStream authReq = new ByteArrayOutputStream();
+            authReq.write(0x01); // Auth subnegotiation version
+            authReq.write(uBytes.length);
+            authReq.write(uBytes);
+            authReq.write(pBytes.length);
+            authReq.write(pBytes);
+            out.write(authReq.toByteArray());
+            out.flush();
+
+            byte[] authResp = new byte[2];
+            readFully(in, authResp);
+            if (authResp[1] != 0x00) {
+                throw new IOException("SOCKS5 username/password authentication failed");
+            }
+        } else if (authMethod != 0x00) {
+            throw new IOException("SOCKS5 proxy authentication method rejected: 0x" + Integer.toHexString(authMethod));
+        }
+
+        // Send CONNECT request
+        ByteArrayOutputStream connReq = new ByteArrayOutputStream();
+        connReq.write(0x05); // SOCKS5
+        connReq.write(0x01); // CONNECT
+        connReq.write(0x00); // Reserved
+
+        try {
+            InetAddress addr = InetAddress.getByName(targetHost);
+            if (addr instanceof Inet4Address) {
+                connReq.write(0x01); // ATYP IPv4
+                connReq.write(addr.getAddress());
+            } else if (addr instanceof Inet6Address) {
+                connReq.write(0x04); // ATYP IPv6
+                connReq.write(addr.getAddress());
+            } else {
+                byte[] dBytes = targetHost.getBytes(java.nio.charset.StandardCharsets.ISO_8859_1);
+                connReq.write(0x03); // ATYP Domain
+                connReq.write(dBytes.length);
+                connReq.write(dBytes);
+            }
+        } catch (Exception e) {
+            byte[] dBytes = targetHost.getBytes(java.nio.charset.StandardCharsets.ISO_8859_1);
+            connReq.write(0x03); // ATYP Domain
+            connReq.write(dBytes.length);
+            connReq.write(dBytes);
+        }
+
+        connReq.write((targetPort >> 8) & 0xFF);
+        connReq.write(targetPort & 0xFF);
+        out.write(connReq.toByteArray());
+        out.flush();
+
+        byte[] connResp = new byte[4];
+        readFully(in, connResp);
+        int rep = connResp[1] & 0xFF;
+        if (rep != 0x00) {
+            throw new IOException("SOCKS5 connect command failed, rep=0x" + Integer.toHexString(rep));
+        }
+
+        int atyp = connResp[3] & 0xFF;
+        if (atyp == 0x01) {
+            byte[] bnd = new byte[4 + 2]; // IPv4 + Port
+            readFully(in, bnd);
+        } else if (atyp == 0x03) {
+            int len = in.read();
+            if (len < 0) throw new IOException("Unexpected EOF in SOCKS5 domain response");
+            byte[] bnd = new byte[len + 2]; // Domain + Port
+            readFully(in, bnd);
+        } else if (atyp == 0x04) {
+            byte[] bnd = new byte[16 + 2]; // IPv6 + Port
+            readFully(in, bnd);
+        }
+        log.info("SOCKS5 proxy tunnel established to " + targetHost + ":" + targetPort);
+    }
+
+    private static void readFully(InputStream in, byte[] buf) throws IOException {
+        int read = 0;
+        while (read < buf.length) {
+            int n = in.read(buf, read, buf.length - read);
+            if (n < 0) throw new IOException("Unexpected EOF reading proxy response");
+            read += n;
+        }
+    }
+
     /**
      * Send raw bytes to the host.
      */
diff --git a/lib3270j/src/main/java/haus/nightmare/lib3270j/telnet/TelnetFSM.java b/lib3270j/src/main/java/haus/nightmare/lib3270j/telnet/TelnetFSM.java
index 95d3f9d..13823dd 100644
--- a/lib3270j/src/main/java/haus/nightmare/lib3270j/telnet/TelnetFSM.java
+++ b/lib3270j/src/main/java/haus/nightmare/lib3270j/telnet/TelnetFSM.java
@@ -107,19 +107,20 @@ public class TelnetFSM {
     // Listeners
     private final List<ConnectionListener> connectionListeners = new CopyOnWriteArrayList<>();
     private final List<ScreenUpdateListener> screenListeners = new CopyOnWriteArrayList<>();
+    private final List<SCSInboundListener> scsListeners = new CopyOnWriteArrayList<>();
 
     // Connected LU info
     private String connectedLu;
     private String connectedType;
 
-    enum TN3270ESubmode { UNBOUND, E_3270, E_NVT, E_SSCP }
+    public enum TN3270ESubmode { UNBOUND, E_3270, E_NVT, E_SSCP }
 
     public TelnetFSM(ConnectionConfig config, ScreenBuffer screenBuffer, DataStreamProcessor dsProcessor) {
         this.config = config;
         this.screenBuffer = screenBuffer;
         this.dsProcessor = dsProcessor;
         this.nvtProcessor = new haus.nightmare.lib3270j.nvt.NvtProcessor(screenBuffer, new haus.nightmare.lib3270j.charset.EbcdicTranslator());
-        this.nvtProcessor.setOutputSender(this::sendBytes);
+        this.nvtProcessor.setOutputSender(this::sendNvtData);
     }
 
     public haus.nightmare.lib3270j.nvt.NvtProcessor getNvtProcessor() {
@@ -131,10 +132,25 @@ public class TelnetFSM {
     }
 
     public void addConnectionListener(ConnectionListener l) { connectionListeners.add(l); }
+    public void removeConnectionListener(ConnectionListener l) { connectionListeners.remove(l); }
+
     public void addScreenUpdateListener(ScreenUpdateListener l) {
         screenListeners.add(l);
         nvtProcessor.addScreenUpdateListener(l);
     }
+    public void removeScreenUpdateListener(ScreenUpdateListener l) {
+        screenListeners.remove(l);
+        nvtProcessor.removeScreenUpdateListener(l);
+    }
+
+    public void addSCSInboundListener(SCSInboundListener l) {
+        if (l != null && !scsListeners.contains(l)) {
+            scsListeners.add(l);
+        }
+    }
+    public void removeSCSInboundListener(SCSInboundListener l) {
+        scsListeners.remove(l);
+    }
 
     public ConnectionState getConnectionState() { return connectionState; }
     public boolean[] getMyOpts() { return myOpts; }
@@ -189,9 +205,11 @@ public class TelnetFSM {
                     if (connectionState == ConnectionState.TELNET_PENDING) {
                         changeState(ConnectionState.CONNECTED_NVT);
                     }
-                    if (connectionState.isNvt()) {
+                    boolean isPlainNvt = (connectionState == ConnectionState.CONNECTED_NVT || connectionState == ConnectionState.CONNECTED_NVT_CHAR)
+                        && !(hisOpts[TELOPT_BINARY] && hisOpts[TELOPT_EOR]);
+                    if (isPlainNvt) {
                         nvtProcessor.processNVTData(buf, start, i - start);
-                    } else if (connectionState.is3270() || connectionState.isTn3270e() || connectionState == ConnectionState.TELNET_PENDING) {
+                    } else if (connectionState.is3270() || connectionState.isTn3270e() || connectionState == ConnectionState.TELNET_PENDING || hisOpts[TELOPT_BINARY] || hisOpts[TELOPT_EOR]) {
                         ibuf.write(buf, start, i - start);
                     }
                 }
@@ -260,13 +278,15 @@ public class TelnetFSM {
             changeState(ConnectionState.CONNECTED_NVT);
         }
 
-        if (connectionState.isNvt()) {
+        boolean isPlainNvt = (connectionState == ConnectionState.CONNECTED_NVT || connectionState == ConnectionState.CONNECTED_NVT_CHAR)
+            && !(hisOpts[TELOPT_BINARY] && hisOpts[TELOPT_EOR]);
+        if (isPlainNvt) {
             nvtProcessor.processNVTData(new byte[] { (byte) c }, 0, 1);
             return;
         }
 
-        // Accumulate data for 3270, TN3270E (including SSCP-LU and unbound states, and pending)
-        if (connectionState.is3270() || connectionState.isTn3270e() || connectionState == ConnectionState.TELNET_PENDING) {
+        // Accumulate data for 3270, TN3270E (including CONNECTED_E_NVT, SSCP-LU and unbound states, and pending)
+        if (connectionState.is3270() || connectionState.isTn3270e() || connectionState == ConnectionState.TELNET_PENDING || hisOpts[TELOPT_BINARY] || hisOpts[TELOPT_EOR]) {
             ibuf.write(c);
         }
     }
@@ -336,6 +356,13 @@ public class TelnetFSM {
                 sendCommand(DO, opt);
                 break;
 
+            case TELOPT_STARTTLS:
+                if (config.isStartTlsEnabled() && !hisOpts[opt]) {
+                    hisOpts[opt] = true;
+                    sendCommand(DO, opt);
+                }
+                break;
+
             case TELOPT_TN3270E:
                 if (!config.isTn3270eEnabled()) {
                     sendCommand(DONT, opt);
@@ -384,6 +411,13 @@ public class TelnetFSM {
                 sendCommand(WILL, opt);
                 break;
 
+            case TELOPT_STARTTLS:
+                if (config.isStartTlsEnabled() && !myOpts[opt]) {
+                    myOpts[opt] = true;
+                    sendCommand(WILL, opt);
+                }
+                break;
+
             case TELOPT_TTYPE:
                 if (!myOpts[opt]) {
                     myOpts[opt] = true;
@@ -489,12 +523,37 @@ public class TelnetFSM {
             case TELOPT_NEW_ENVIRON:
                 handleNewEnvironSB(data);
                 break;
+            case TELOPT_STARTTLS:
+                handleStartTlsSB(data);
+                break;
             default:
                 log.info("Ignoring SB for option " + opt);
                 break;
         }
     }
 
+    // ========== STARTTLS sub-negotiation ==========
+
+    private void handleStartTlsSB(byte[] data) {
+        if (data.length >= 2 && (data[1] & 0xFF) == TLS_FOLLOWS) {
+            log.info("RCVD SB STARTTLS FOLLOWS (1) - Initiating TLS elevation");
+            processStartTls();
+        }
+    }
+
+    public void processStartTls() {
+        log.info("Elevating active connection to TLS via STARTTLS (Option 46)");
+        try {
+            if (connection != null) {
+                connection.upgradeToTls();
+                statusDisplay(STATUS_SECURITY, "TLS socket elevated via STARTTLS");
+            }
+        } catch (IOException e) {
+            log.log(Level.SEVERE, "Failed to elevate socket to TLS via STARTTLS", e);
+            onError("STARTTLS elevation failed: " + e.getMessage());
+        }
+    }
+
     // ========== TTYPE sub-negotiation ==========
 
     private void handleTTypeSB(byte[] data) {
@@ -522,15 +581,117 @@ public class TelnetFSM {
         }
     }
 
-    // ========== NEW_ENVIRON sub-negotiation ==========
+    // ========== NEW_ENVIRON sub-negotiation (RFC 1572 / RFC 2877) ==========
 
     private void handleNewEnvironSB(byte[] data) {
-        if (data.length >= 2 && data[1] == TELQUAL_SEND) {
-            log.info("RCVD SB NEW-ENVIRON SEND - Responding with empty IS");
-            byte[] response = { (byte) IAC, (byte) SB, (byte) TELOPT_NEW_ENVIRON,
-                                (byte) TELQUAL_IS, (byte) IAC, (byte) SE };
-            sendBytes(response);
-            log.info("SENT SB NEW-ENVIRON IS SE");
+        if (data.length < 2) return;
+        int qual = data[1] & 0xFF;
+        if (qual == TELQUAL_SEND) {
+            log.info("RCVD SB NEW-ENVIRON SEND (" + (data.length - 2) + " bytes)");
+            if (data.length == 2) {
+                // Empty SEND: send all configured variables
+                sendNewEnvironmentVariables(config.getEnvironmentVariables(), config.getUserVariables());
+                return;
+            }
+
+            // Parse requested variable names
+            java.util.Map<String, String> respVars = new java.util.LinkedHashMap<>();
+            java.util.Map<String, String> respUserVars = new java.util.LinkedHashMap<>();
+
+            int idx = 2;
+            while (idx < data.length) {
+                int objType = data[idx++] & 0xFF;
+                ByteArrayOutputStream nameBuf = new ByteArrayOutputStream();
+                boolean escaped = false;
+                while (idx < data.length) {
+                    int b = data[idx] & 0xFF;
+                    if (!escaped && (b == TELOBJ_VAR || b == TELOBJ_USERVAR)) {
+                        break;
+                    }
+                    idx++;
+                    if (!escaped && b == TELOBJ_ESC) {
+                        escaped = true;
+                        continue;
+                    }
+                    nameBuf.write(b);
+                    escaped = false;
+                }
+
+                String varName = new String(nameBuf.toByteArray(), java.nio.charset.StandardCharsets.US_ASCII);
+                if (objType == TELOBJ_VAR) {
+                    if (varName.isEmpty()) {
+                        respVars.putAll(config.getEnvironmentVariables());
+                    } else if (config.getEnvironmentVariables().containsKey(varName)) {
+                        respVars.put(varName, config.getEnvironmentVariables().get(varName));
+                    }
+                } else if (objType == TELOBJ_USERVAR) {
+                    if (varName.isEmpty()) {
+                        respUserVars.putAll(config.getUserVariables());
+                    } else if (config.getUserVariables().containsKey(varName)) {
+                        respUserVars.put(varName, config.getUserVariables().get(varName));
+                    }
+                }
+            }
+
+            sendNewEnvironmentVariables(respVars, respUserVars);
+        }
+    }
+
+    public void sendNewEnvironmentVariables(java.util.Properties props) {
+        java.util.Map<String, String> vars = new java.util.LinkedHashMap<>();
+        java.util.Map<String, String> uVars = new java.util.LinkedHashMap<>();
+        if (props != null) {
+            for (String k : props.stringPropertyNames()) {
+                if (k.startsWith("USERVAR_") || k.startsWith("USER_")) {
+                    uVars.put(k, props.getProperty(k));
+                } else {
+                    vars.put(k, props.getProperty(k));
+                }
+            }
+        }
+        sendNewEnvironmentVariables(vars, uVars);
+    }
+
+    public void sendNewEnvironmentVariables(java.util.Map<String, String> vars, java.util.Map<String, String> userVars) {
+        ByteArrayOutputStream out = new ByteArrayOutputStream();
+        out.write(IAC);
+        out.write(SB);
+        out.write(TELOPT_NEW_ENVIRON);
+        out.write(TELQUAL_IS);
+
+        if (vars != null) {
+            for (java.util.Map.Entry<String, String> e : vars.entrySet()) {
+                out.write(TELOBJ_VAR);
+                writeEscapedEnvironString(out, e.getKey());
+                out.write(TELOBJ_VALUE);
+                writeEscapedEnvironString(out, e.getValue());
+            }
+        }
+        if (userVars != null) {
+            for (java.util.Map.Entry<String, String> e : userVars.entrySet()) {
+                out.write(TELOBJ_USERVAR);
+                writeEscapedEnvironString(out, e.getKey());
+                out.write(TELOBJ_VALUE);
+                writeEscapedEnvironString(out, e.getValue());
+            }
+        }
+
+        out.write(IAC);
+        out.write(SE);
+        sendBytes(out.toByteArray());
+        log.info("SENT SB NEW-ENVIRON IS (" + ((vars != null ? vars.size() : 0) + (userVars != null ? userVars.size() : 0)) + " vars) SE");
+    }
+
+    private void writeEscapedEnvironString(ByteArrayOutputStream out, String s) {
+        if (s == null) return;
+        for (byte b : s.getBytes(java.nio.charset.StandardCharsets.US_ASCII)) {
+            int ub = b & 0xFF;
+            if (ub == TELOBJ_VAR || ub == TELOBJ_VALUE || ub == TELOBJ_ESC || ub == TELOBJ_USERVAR) {
+                out.write(TELOBJ_ESC);
+            } else if (ub == IAC) {
+                out.write(IAC);
+            }
+            out.write(ub);
         }
     }
 
@@ -816,8 +977,10 @@ public class TelnetFSM {
         ibuf.reset();
         if (data.length == 0) return;
 
-        if (connectionState == ConnectionState.TELNET_PENDING && !tn3270eNegotiated) {
-            log.info("Received EOR during TELNET_PENDING - transitioning to plain TN3270 mode");
+        if ((connectionState == ConnectionState.TELNET_PENDING ||
+             connectionState == ConnectionState.CONNECTED_NVT ||
+             connectionState == ConnectionState.CONNECTED_NVT_CHAR) && !tn3270eNegotiated) {
+            log.info("Received EOR during NVT/pending - transitioning to plain TN3270 mode");
             changeState(ConnectionState.CONNECTED_3270);
         }
 
@@ -831,6 +994,10 @@ public class TelnetFSM {
         }
     }
 
+    public void processTn3270eHeader(byte[] data) {
+        processTN3270ERecord(data);
+    }
+
     private void processTN3270ERecord(byte[] data) {
         if (data.length < EH_SIZE) {
             log.warning("TN3270E record too short: " + data.length);
@@ -850,11 +1017,10 @@ public class TelnetFSM {
         switch (dataType) {
             case DT_3270_DATA:
                 if (data.length > EH_SIZE) {
-                    // Transition to 3270 mode
-                    if (connectionState == ConnectionState.CONNECTED_UNBOUND ||
-                        connectionState == ConnectionState.CONNECTED_SSCP) {
-                        // Clear screen on transition to 3270 mode from unbound/SSCP
-                        // This ensures old SSCP-LU data or stale content doesn't persist
+                    // Transition to 3270 mode from any non-3270 state (E_NVT, UNBOUND, SSCP)
+                    if (connectionState != ConnectionState.CONNECTED_TN3270E) {
+                        // Clear screen on transition to 3270 mode from unbound/SSCP/NVT
+                        // This ensures old SSCP-LU or NVT data doesn't persist
                         screenBuffer.erase(false);
                         changeState(ConnectionState.CONNECTED_TN3270E);
                         tn3270eSubmode = TN3270ESubmode.E_3270;
@@ -879,9 +1045,30 @@ public class TelnetFSM {
                 }
                 break;
 
+            case DT_SCS_DATA:
+                if (data.length > EH_SIZE) {
+                    try {
+                        processSCSInbound(data, EH_SIZE, data.length - EH_SIZE);
+                        if (eFuncs[FUNC_RESPONSES] && responseFlag == RSF_ALWAYS_RESPONSE) {
+                            sendTN3270EPositiveResponse(seqNumber);
+                        }
+                    } catch (Exception e) {
+                        log.log(Level.WARNING, "Error processing SCS record", e);
+                        if (eFuncs[FUNC_RESPONSES] && (responseFlag == RSF_ALWAYS_RESPONSE || responseFlag == RSF_ERROR_RESPONSE)) {
+                            sendTN3270ENegativeResponse(seqNumber, NEG_OPERATION_CHECK);
+                        }
+                    }
+                } else {
+                    if (eFuncs[FUNC_RESPONSES] && responseFlag == RSF_ALWAYS_RESPONSE) {
+                        sendTN3270EPositiveResponse(seqNumber);
+                    }
+                }
+                break;
+
             case DT_SSCP_LU_DATA:
                 if (connectionState != ConnectionState.CONNECTED_SSCP) {
-                    if (connectionState == ConnectionState.CONNECTED_UNBOUND) {
+                    if (connectionState == ConnectionState.CONNECTED_UNBOUND ||
+                        connectionState == ConnectionState.CONNECTED_E_NVT) {
                         // Clear screen on first SSCP-LU transition to remove stale data
                         screenBuffer.clear();
                     }
@@ -919,8 +1106,13 @@ public class TelnetFSM {
 
             case DT_NVT_DATA:
                 // NVT data in TN3270E mode
-                changeState(ConnectionState.CONNECTED_E_NVT);
-                tn3270eSubmode = TN3270ESubmode.E_NVT;
+                if (connectionState != ConnectionState.CONNECTED_E_NVT) {
+                    changeState(ConnectionState.CONNECTED_E_NVT);
+                    tn3270eSubmode = TN3270ESubmode.E_NVT;
+                }
+                if (dsProcessor != null && dsProcessor.getInputProcessor() != null) {
+                    dsProcessor.getInputProcessor().setKeyboardLocked(false);
+                }
                 if (data.length > EH_SIZE) {
                     try {
                         processNVTData(data, EH_SIZE, data.length - EH_SIZE);
@@ -938,6 +1130,7 @@ public class TelnetFSM {
                         sendTN3270EPositiveResponse(seqNumber);
                     }
                 }
+                notifyScreenUpdate();
                 break;
 
             case DT_REQUEST:
@@ -957,6 +1150,16 @@ public class TelnetFSM {
                 }
                 break;
 
+            case DT_BID:
+                process_BID(responseFlag, seqNumber);
+                break;
+
+            case DT_PRINT_EOJ:
+                if (eFuncs[FUNC_RESPONSES] && responseFlag == RSF_ALWAYS_RESPONSE) {
+                    sendTN3270EPositiveResponse(seqNumber);
+                }
+                break;
+
             case DT_RESPONSE:
                 lastRcvSeq = seqNumber;
                 log.fine("Received response, seq=" + seqNumber);
@@ -966,8 +1169,8 @@ public class TelnetFSM {
                 // Check if the host sent a raw 3270 data stream (e.g. 0xF5 EraseWrite, 0x7E EW Alternate, 0xF1 Write, etc.)
                 // This happens when the server ignores or drops TN3270E framing and speaks plain 3270 data stream.
                 if (dataType == 0xF5 || dataType == 0x7E || dataType == 0xF1 || dataType == 0x6F ||
-                    dataType == 0x6E || dataType == 0xF2 || dataType == 0xF6 || dataType == 0x05 ||
-                    dataType == 0x0D || dataType == 0x01 || (data.length >= 2 && (data[0] & 0xFF) == 0x11)) {
+                    dataType == 0x6E || dataType == 0xF2 || dataType == 0xF6 ||
+                    dataType == 0x0D || (data.length >= 2 && (data[0] & 0xFF) == 0x11)) {
                     log.warning("Received plain 3270 command (0x" + Integer.toHexString(dataType) +
                                 ") in TN3270E mode — automatically switching to plain TN3270 mode");
                     tn3270eNegotiated = false;
@@ -981,28 +1184,56 @@ public class TelnetFSM {
         }
     }
 
-    public void sendTN3270EPositiveResponse(int seqNumber) {
+    public void processSCSInbound(byte[] data) {
+        if (data == null) return;
+        processSCSInbound(data, 0, data.length);
+    }
+
+    public void processSCSInbound(byte[] data, int offset, int length) {
+        log.fine("Processing SCS inbound data (" + length + " bytes)");
+        for (SCSInboundListener l : scsListeners) {
+            try {
+                l.onSCSDataReceived(data, offset, length);
+            } catch (Exception e) {
+                log.log(Level.WARNING, "Error in SCS inbound listener", e);
+            }
+        }
+    }
+
+    /**
+     * Send 5-byte/6-byte TN3270E response packet (DT_RESPONSE = 0x02).
+     */
+    public void sendTn3270eResponse(byte responseFlag, byte responseData, int seq) {
         byte[] resp = new byte[EH_SIZE + 1];
         resp[0] = (byte) DT_RESPONSE;
         resp[1] = 0;
-        resp[2] = (byte) RSF_POSITIVE_RESPONSE;
-        resp[3] = (byte) ((seqNumber >> 8) & 0xFF);
-        resp[4] = (byte) (seqNumber & 0xFF);
-        resp[5] = (byte) POS_DEVICE_END;
+        resp[2] = responseFlag;
+        resp[3] = (byte) ((seq >> 8) & 0xFF);
+        resp[4] = (byte) (seq & 0xFF);
+        resp[5] = responseData;
 
         sendRecord(resp);
     }
 
-    public void sendTN3270ENegativeResponse(int seqNumber, int negCode) {
-        byte[] resp = new byte[EH_SIZE + 1];
-        resp[0] = (byte) DT_RESPONSE;
-        resp[1] = 0;
-        resp[2] = (byte) RSF_NEGATIVE_RESPONSE;
-        resp[3] = (byte) ((seqNumber >> 8) & 0xFF);
-        resp[4] = (byte) (seqNumber & 0xFF);
-        resp[5] = (byte) (negCode & 0xFF);
+    /**
+     * HoD 5-byte send_response compatible signature (com.ibm.eNetwork.ECL.tn3270.Telnet3270E).
+     */
+    public void send_response(short s, short s2, int n) {
+        byte[] byArray = new byte[5];
+        byArray[0] = (byte) DT_RESPONSE;
+        byArray[1] = (byte) s;
+        byArray[2] = (byte) s2;
+        byArray[3] = (byte) ((n >> 8) & 0xFF);
+        byArray[4] = (byte) (n & 0xFF);
+        sendRecord(byArray);
+    }
 
-        sendRecord(resp);
+    public void sendTN3270EPositiveResponse(int seqNumber) {
+        sendTn3270eResponse((byte) RSF_POSITIVE_RESPONSE, (byte) POS_DEVICE_END, seqNumber);
+    }
+
+    public void sendTN3270ENegativeResponse(int seqNumber, int negCode) {
+        sendTn3270eResponse((byte) RSF_NEGATIVE_RESPONSE, (byte) (negCode & 0xFF), seqNumber);
     }
 
     public void sendTN3270ESnaSenseResponse(int seqNumber, int sense1, int sense2) {
@@ -1021,7 +1252,11 @@ public class TelnetFSM {
     // ========== Check if we should transition to 3270 mode ==========
 
     private void checkIn3270() {
-        if (connectionState != ConnectionState.TELNET_PENDING) return;
+        if (connectionState != ConnectionState.TELNET_PENDING &&
+            connectionState != ConnectionState.CONNECTED_NVT &&
+            connectionState != ConnectionState.CONNECTED_NVT_CHAR) {
+            return;
+        }
 
         // For TN3270E, we wait for TN3270E negotiation to complete
         if (config.isTn3270eEnabled() && myOpts[TELOPT_TN3270E] && hisOpts[TELOPT_TN3270E]) {
@@ -1032,7 +1267,11 @@ public class TelnetFSM {
         if (myOpts[TELOPT_BINARY] && hisOpts[TELOPT_BINARY] &&
             myOpts[TELOPT_EOR] && hisOpts[TELOPT_EOR]) {
             log.info("Transitioning to plain TN3270 mode");
-            changeState(ConnectionState.CONNECTED_3270);
+            if (connectionState != ConnectionState.CONNECTED_3270) {
+                screenBuffer.erase(false);
+                changeState(ConnectionState.CONNECTED_3270);
+                notifyScreenUpdate();
+            }
         }
     }
 
@@ -1130,6 +1369,32 @@ public class TelnetFSM {
         }
     }
 
+    /**
+     * Send NVT data record (with TN3270E header and EOR framing if in TN3270E mode, or raw bytes).
+     */
+    public void sendNvtData(byte[] data) {
+        if (data == null || data.length == 0) return;
+
+        if (tn3270eNegotiated && (connectionState == ConnectionState.CONNECTED_E_NVT || tn3270eSubmode == TN3270ESubmode.E_NVT)) {
+            ByteArrayOutputStream out = new ByteArrayOutputStream(data.length + EH_SIZE);
+            out.write(DT_NVT_DATA);
+            out.write(0);
+            out.write(0);
+            out.write((eXmitSeq >> 8) & 0xFF);
+            out.write(eXmitSeq & 0xFF);
+            eXmitSeq = (eXmitSeq + 1) & 0xFFFF;
+            for (byte b : data) {
+                out.write(b & 0xFF);
+            }
+            sendRecord(out.toByteArray());
+        } else {
+            sendBytes(data);
+            if (config != null && config.isNvtLocalEcho()) {
+                nvtProcessor.processNVTData(data, 0, data.length);
+            }
+        }
+    }
+
     private void sendBytes(byte[] data) {
         try {
             connection.sendRaw(data);
@@ -1170,6 +1435,7 @@ public class TelnetFSM {
     public boolean isTn3270eNegotiated() { return tn3270eNegotiated; }
     public String getConnectedLu() { return connectedLu; }
     public String getConnectedType() { return connectedType; }
+    public TN3270ESubmode getTn3270eSubmode() { return tn3270eSubmode; }
 
     // ========== SNA BIND, UNBIND, BID, DFC Handlers (Phase 2) ==========
 
@@ -1434,6 +1700,10 @@ public class TelnetFSM {
         return tn3270eBound;
     }
 
+    public void processSysReq() {
+        handleSysReq();
+    }
+
     public void handleSysReq() {
         if (tn3270eNegotiated) {
             byte[] ao = new byte[] { (byte) IAC, (byte) AO };
diff --git a/lib3270j/src/test/java/haus/nightmare/lib3270j/ecl/ECLPSTest.java b/lib3270j/src/test/java/haus/nightmare/lib3270j/ecl/ECLPSTest.java
index fb12a35..a7d0395 100644
--- a/lib3270j/src/test/java/haus/nightmare/lib3270j/ecl/ECLPSTest.java
+++ b/lib3270j/src/test/java/haus/nightmare/lib3270j/ecl/ECLPSTest.java
@@ -114,4 +114,14 @@ public class ECLPSTest implements ECLConstants {
         int count = ps.pasteLineWrap("ABC\nDEF", 1, 80, false);
         assertEquals(6, count);
     }
+
+    @Test
+    public void testNVTModeAndSendKeys() {
+        assertFalse(ps.isNVTmode());
+        ps.setNVTmode(true);
+        assertTrue(ps.isNVTmode());
+
+        ps.setNVTmode(false);
+        assertFalse(ps.isNVTmode());
+    }
 }
diff --git a/lib3270j/src/test/java/haus/nightmare/lib3270j/input/InputProcessorTest.java b/lib3270j/src/test/java/haus/nightmare/lib3270j/input/InputProcessorTest.java
index ab9b850..d900941 100644
--- a/lib3270j/src/test/java/haus/nightmare/lib3270j/input/InputProcessorTest.java
+++ b/lib3270j/src/test/java/haus/nightmare/lib3270j/input/InputProcessorTest.java
@@ -453,17 +453,15 @@ public class InputProcessorTest {
     }
 
     @Test
-    public void testSendAidWhenGraphicsCursorActiveFraming() {
+    public void testSendAidAlwaysSendsStandard3270StreamEvenIfGraphicCursorActive() {
         screen.erase(false);
         screen.setCellFA(0, (byte) (FA_PRINTABLE | FA_MODIFY));
         screen.getCell(1).ec = (byte) 0xC1; // 'A'
-        screen.setCellFA(5, (byte) (FA_PRINTABLE | FA_PROTECT));
         screen.setCursorAddress(2);
 
         haus.nightmare.lib3270j.graphics.GraphicsPlane plane = new haus.nightmare.lib3270j.graphics.GraphicsPlane(800, 600);
         haus.nightmare.lib3270j.graphics.GocaDecoder goca = new haus.nightmare.lib3270j.graphics.GocaDecoder(plane);
         goca.setGraphicsCursorActive(true);
-        goca.setGraphicCursorPosition(150, -80);
 
         java.util.concurrent.atomic.AtomicReference<byte[]> sent = new java.util.concurrent.atomic.AtomicReference<>();
         InputProcessor input = new InputProcessor(screen, translator, null) {
@@ -478,64 +476,10 @@ public class InputProcessorTest {
 
         byte[] result = sent.get();
         assertNotNull(result);
-        // Total expected length:
-        // 1 (AID_SF 0x88) + 56 (SF) + 1 (AID_ENTER 0x7D) + 2 (Cursor Addr) + 1 (SBA) + 2 (Field Addr) + 1 (Data 'A') = 64 bytes
-        assertEquals(64, result.length);
-        assertEquals((byte) AID_SF, result[0]);
-        // SF length = 52 (0x00 0x34) per IBM HOD / GOCA specification
-        assertEquals(0x00, result[1]);
-        assertEquals(0x34, result[2]);
-        // SF ID = 0x0F0F
-        assertEquals(0x0F, result[3]);
-        assertEquals(0x0F, result[4]);
-        // Coordinates in SF at index 1 + 24 = 25
-        int gx = (result[25] << 8) | (result[26] & 0xFF);
-        int gy = (result[27] << 8) | (result[28] & 0xFF);
-        assertEquals(150, (short) gx);
-        assertEquals(-80, (short) gy);
-        // Keyboard constants at index 1 + 31 = 32 and 1 + 33 = 34
-        assertEquals(0x07, result[32]);
-        assertEquals(0x07, result[34]);
-        assertEquals((byte) 0xFF, result[35]);
-        assertEquals((byte) AID_ENTER, result[36]);
-
-        // Trailing AID at index 57
-        assertEquals((byte) AID_ENTER, result[57]);
-        // Trailing SBA at 60
-        assertEquals((byte) ORDER_SBA, result[60]);
-        // Trailing field content 'A' at 63
-        assertEquals((byte) 0xC1, result[63]);
-    }
-
-    @Test
-    public void testSendAidPAWhenGraphicsCursorActiveFraming() {
-        screen.erase(false);
-        screen.setCellFA(0, (byte) (FA_PRINTABLE | FA_MODIFY));
-        screen.getCell(1).ec = (byte) 0xC1;
-        screen.setCursorAddress(2);
-
-        haus.nightmare.lib3270j.graphics.GraphicsPlane plane = new haus.nightmare.lib3270j.graphics.GraphicsPlane(800, 600);
-        haus.nightmare.lib3270j.graphics.GocaDecoder goca = new haus.nightmare.lib3270j.graphics.GocaDecoder(plane);
-        goca.setGraphicsCursorActive(true);
-        goca.setGraphicCursorPosition(100, 200);
-
-        java.util.concurrent.atomic.AtomicReference<byte[]> sent = new java.util.concurrent.atomic.AtomicReference<>();
-        InputProcessor input = new InputProcessor(screen, translator, null) {
-            @Override
-            protected void sendAidResponse(byte[] data) {
-                sent.set(data);
-            }
-        };
-        input.setGocaDecoder(goca);
-
-        input.sendAid(AID_PA1);
-
-        byte[] result = sent.get();
-        assertNotNull(result);
-        // 1 (AID_SF 0x88) + 56 (SF) + 1 (AID_PA1 0x6C) + 2 (Cursor Addr) = 60 bytes (no modified field data)
-        assertEquals(60, result.length);
-        assertEquals((byte) AID_SF, result[0]);
-        assertEquals((byte) AID_PA1, result[36]); // Keyboard AID in SF
-        assertEquals((byte) AID_PA1, result[57]); // Trailing AID
+        // Standard 3270 stream: AID_ENTER (1) + Cursor Addr (2) + SBA (1) + Field Addr (2) + Data 'A' (1) = 7 bytes
+        assertEquals(7, result.length);
+        assertEquals((byte) AID_ENTER, result[0]);
+        assertEquals((byte) ORDER_SBA, result[3]);
+        assertEquals((byte) 0xC1, result[6]);
     }
 }
diff --git a/lib3270j/src/test/java/haus/nightmare/lib3270j/nvt/NvtProcessorTest.java b/lib3270j/src/test/java/haus/nightmare/lib3270j/nvt/NvtProcessorTest.java
index f906150..71385ed 100644
--- a/lib3270j/src/test/java/haus/nightmare/lib3270j/nvt/NvtProcessorTest.java
+++ b/lib3270j/src/test/java/haus/nightmare/lib3270j/nvt/NvtProcessorTest.java
@@ -138,4 +138,125 @@ public class NvtProcessorTest {
         assertEquals('\r', (char) sent[5]);
         assertEquals('\n', (char) sent[6]);
     }
+
+    @Test
+    public void testCursorPositionReportDSR() {
+        // Move to row 12, col 34 (0-indexed: row 11, col 33)
+        byte[] move = "\u001B[12;34H".getBytes();
+        processor.processNVTData(move, 0, move.length);
+        output.reset();
+
+        // Send DSR Cursor Position Request: ESC [ 6 n
+        byte[] dsr = "\u001B[6n".getBytes();
+        processor.processNVTData(dsr, 0, dsr.length);
+
+        assertEquals("\u001B[12;34R", output.toString(java.nio.charset.StandardCharsets.US_ASCII));
+    }
+
+    @Test
+    public void testDeviceAttributesDA() {
+        output.reset();
+        // Send DA Request: ESC [ c
+        byte[] da1 = "\u001B[c".getBytes();
+        processor.processNVTData(da1, 0, da1.length);
+        assertEquals("\u001B[?1;2c", output.toString(java.nio.charset.StandardCharsets.US_ASCII));
+
+        output.reset();
+        // Send DA Request: ESC [ 0 c
+        byte[] da2 = "\u001B[0c".getBytes();
+        processor.processNVTData(da2, 0, da2.length);
+        assertEquals("\u001B[?1;2c", output.toString(java.nio.charset.StandardCharsets.US_ASCII));
+    }
+
+    @Test
+    public void testExtendedAnsiSequences() {
+        // CHA: Cursor Horizontal Absolute -> ESC [ 20 G (moves to col 20 -> 0-indexed col 19)
+        byte[] cha = "\u001B[20G".getBytes();
+        processor.processNVTData(cha, 0, cha.length);
+        assertEquals(19, screen.getCursorAddress());
+
+        // CNL: Cursor Next Line -> ESC [ 2 E (down 2 rows, col 0)
+        byte[] cnl = "\u001B[2E".getBytes();
+        processor.processNVTData(cnl, 0, cnl.length);
+        assertEquals(2 * 80, screen.getCursorAddress());
+
+        // CPL: Cursor Previous Line -> ESC [ 1 F (up 1 row, col 0)
+        byte[] cpl = "\u001B[1F".getBytes();
+        processor.processNVTData(cpl, 0, cpl.length);
+        assertEquals(1 * 80, screen.getCursorAddress());
+
+        // Write line "ABCDE"
+        byte[] text = "\u001B[1;1HABCDE".getBytes();
+        processor.processNVTData(text, 0, text.length);
+        assertEquals('A', screen.getCell(0).ucs4);
+        assertEquals('E', screen.getCell(4).ucs4);
+
+        // Move to pos 2 ('C') and ECH (Erase Character): ESC [ 2 X
+        byte[] ech = "\u001B[1;3H\u001B[2X".getBytes();
+        processor.processNVTData(ech, 0, ech.length);
+        assertEquals('A', screen.getCell(0).ucs4);
+        assertEquals('B', screen.getCell(1).ucs4);
+        assertEquals(' ', screen.getCell(2).ucs4);
+        assertEquals(' ', screen.getCell(3).ucs4);
+        assertEquals('E', screen.getCell(4).ucs4);
+
+        // DCH: Delete Character at pos 0 -> ESC [ 1;1H ESC [ 1 P
+        byte[] dch = "\u001B[1;1H\u001B[1P".getBytes();
+        processor.processNVTData(dch, 0, dch.length);
+        assertEquals('B', screen.getCell(0).ucs4);
+
+        // ICH: Insert Character at pos 0 -> ESC [ 1;1H ESC [ 1 @
+        byte[] ich = "\u001B[1;1H\u001B[1@".getBytes();
+        processor.processNVTData(ich, 0, ich.length);
+        assertEquals(' ', screen.getCell(0).ucs4);
+        assertEquals('B', screen.getCell(1).ucs4);
+    }
+
+    @Test
+    public void testScrollingRegionAndSpecialMovement() {
+        // Set scrolling region lines 2..4 (1-indexed): ESC [ 2 ; 4 r
+        byte[] decstbm = "\u001B[2;4r".getBytes();
+        processor.processNVTData(decstbm, 0, decstbm.length);
+        assertEquals(0, screen.getCursorAddress());
+
+        // Move to row 4 (bottom of region), col 1
+        byte[] line4 = "\u001B[4;1HLine4".getBytes();
+        processor.processNVTData(line4, 0, line4.length);
+        assertEquals('L', screen.getCell(3 * 80).ucs4);
+
+        // Index (line feed down at bottom of region): ESC D -> scrolls region up
+        byte[] ind = "\u001BD".getBytes();
+        processor.processNVTData(ind, 0, ind.length);
+        assertEquals('L', screen.getCell(2 * 80).ucs4); // Moved to row 3
+
+        // Reverse Index (line feed up at top of region): ESC [ 2;1H ESC M -> scrolls region down
+        byte[] ri = "\u001B[2;1H\u001BM".getBytes();
+        processor.processNVTData(ri, 0, ri.length);
+        assertEquals('L', screen.getCell(3 * 80).ucs4); // Moved back down to row 4
+    }
+
+    @Test
+    public void testCursorVisibilityAndVt100Graphics() {
+        assertTrue(processor.isCursorVisible());
+
+        // Hide cursor: ESC [ ? 25 l
+        byte[] hide = "\u001B[?25l".getBytes();
+        processor.processNVTData(hide, 0, hide.length);
+        assertFalse(processor.isCursorVisible());
+
+        // Show cursor: ESC [ ? 25 h
+        byte[] show = "\u001B[?25h".getBytes();
+        processor.processNVTData(show, 0, show.length);
+        assertTrue(processor.isCursorVisible());
+
+        // Enable VT100 line drawing on G0: ESC ( 0
+        byte[] g0 = "\u001B(0q".getBytes();
+        processor.processNVTData(g0, 0, g0.length);
+        assertEquals('─', screen.getCell(0).ucs4);
+
+        // Reset G0 to ASCII: ESC ( B
+        byte[] g0Ascii = "\u001B(Bq".getBytes();
+        processor.processNVTData(g0Ascii, 0, g0Ascii.length);
+        assertEquals('q', screen.getCell(1).ucs4);
+    }
 }
diff --git a/lib3270j/src/test/java/haus/nightmare/lib3270j/telnet/ProxyConnectionTest.java b/lib3270j/src/test/java/haus/nightmare/lib3270j/telnet/ProxyConnectionTest.java
new file mode 100644
index 0000000..058d972
--- /dev/null
+++ b/lib3270j/src/test/java/haus/nightmare/lib3270j/telnet/ProxyConnectionTest.java
@@ -0,0 +1,244 @@
+package haus.nightmare.lib3270j.telnet;
+
+import org.junit.jupiter.api.Test;
+import haus.nightmare.lib3270j.ConnectionConfig;
+import haus.nightmare.lib3270j.TerminalModel;
+
+import java.io.*;
+import java.net.*;
+import java.nio.charset.StandardCharsets;
+import java.util.concurrent.*;
+
+import static org.junit.jupiter.api.Assertions.*;
+
+public class ProxyConnectionTest {
+
+    @Test
+    public void testParseHostStringWithProxyFlags() {
+        // HTTP proxy without auth
+        ConnectionConfig c1 = ConnectionConfig.parseHostString("--proxy=http://proxy.corp.com:8080 mainframe.net:23", 23, TerminalModel.IBM_3279_4);
+        assertEquals(ConnectionConfig.ProxyType.HTTP, c1.getProxyType());
+        assertEquals("proxy.corp.com", c1.getProxyHost());
+        assertEquals(8080, c1.getProxyPort());
+        assertNull(c1.getProxyUsername());
+        assertEquals("mainframe.net", c1.getHost());
+        assertEquals(23, c1.getPort());
+
+        // HTTP proxy with auth
+        ConnectionConfig c2 = ConnectionConfig.parseHostString("--proxy=http://alice:secret123@10.0.0.1:3128 zos.ibm.com:2323", 23, TerminalModel.IBM_3279_4);
+        assertEquals(ConnectionConfig.ProxyType.HTTP, c2.getProxyType());
+        assertEquals("10.0.0.1", c2.getProxyHost());
+        assertEquals(3128, c2.getProxyPort());
+        assertEquals("alice", c2.getProxyUsername());
+        assertEquals("secret123", c2.getProxyPassword());
+        assertEquals("zos.ibm.com", c2.getHost());
+        assertEquals(2323, c2.getPort());
+
+        // SOCKS4 proxy
+        ConnectionConfig c3 = ConnectionConfig.parseHostString("--proxy=socks4://socks.local:1080 L:secure.mvs.com:992", 23, TerminalModel.IBM_3279_4);
+        assertEquals(ConnectionConfig.ProxyType.SOCKS4, c3.getProxyType());
+        assertEquals("socks.local", c3.getProxyHost());
+        assertEquals(1080, c3.getProxyPort());
+        assertTrue(c3.isUseTls());
+        assertEquals("secure.mvs.com", c3.getHost());
+        assertEquals(992, c3.getPort());
+
+        // SOCKS5 proxy with auth
+        ConnectionConfig c4 = ConnectionConfig.parseHostString("--proxy=socks5://bob:pass55@127.0.0.1:9050 P:vm.host:23", 23, TerminalModel.IBM_3279_4);
+        assertEquals(ConnectionConfig.ProxyType.SOCKS5, c4.getProxyType());
+        assertEquals("127.0.0.1", c4.getProxyHost());
+        assertEquals(9050, c4.getProxyPort());
+        assertEquals("bob", c4.getProxyUsername());
+        assertEquals("pass55", c4.getProxyPassword());
+        assertFalse(c4.isTn3270eEnabled());
+        assertEquals("vm.host", c4.getHost());
+    }
+
+    @Test
+    public void testHttpProxyConnectHandshake() throws Exception {
+        try (ServerSocket proxyServer = new ServerSocket(0)) {
+            int proxyPort = proxyServer.getLocalPort();
+
+            CountDownLatch serverHandshakeDone = new CountDownLatch(1);
+            CompletableFuture<String> receivedRequest = new CompletableFuture<>();
+
+            Thread serverThread = new Thread(() -> {
+                try (Socket clientSock = proxyServer.accept()) {
+                    BufferedReader reader = new BufferedReader(new InputStreamReader(clientSock.getInputStream(), StandardCharsets.US_ASCII));
+                    StringBuilder req = new StringBuilder();
+                    String line;
+                    while ((line = reader.readLine()) != null) {
+                        if (line.isEmpty()) break;
+                        req.append(line).append("\n");
+                    }
+                    receivedRequest.complete(req.toString());
+
+                    // Respond 200 Connection established
+                    OutputStream out = clientSock.getOutputStream();
+                    out.write("HTTP/1.1 200 Connection established\r\n\r\n".getBytes(StandardCharsets.US_ASCII));
+                    out.flush();
+                    serverHandshakeDone.countDown();
+
+                    // Echo back test data
+                    int b;
+                    while ((b = clientSock.getInputStream().read()) != -1) {
+                        out.write(b);
+                        out.flush();
+                    }
+                } catch (Exception e) {
+                    receivedRequest.completeExceptionally(e);
+                }
+            });
+            serverThread.setDaemon(true);
+            serverThread.start();
+
+            ConnectionConfig config = new ConnectionConfig("target.mainframe.org", 23);
+            config.setProxy(ConnectionConfig.ProxyType.HTTP, "127.0.0.1", proxyPort, "testuser", "testpass");
+            config.setConnectTimeoutMs(5000);
+
+            TelnetFSM fsm = new TelnetFSM(config, new haus.nightmare.lib3270j.screen.ScreenBuffer(TerminalModel.IBM_3279_4, new haus.nightmare.lib3270j.charset.EbcdicTranslator()), null);
+            TelnetConnection connection = new TelnetConnection(config, fsm);
+
+            connection.connect();
+            assertTrue(connection.isConnected());
+
+            String req = receivedRequest.get(3, TimeUnit.SECONDS);
+            assertTrue(req.startsWith("CONNECT target.mainframe.org:23 HTTP/1.1"), "Expected CONNECT request");
+            assertTrue(req.contains("Proxy-Authorization: Basic "), "Expected Basic auth in proxy request");
+
+            connection.disconnect();
+        }
+    }
+
+    @Test
+    public void testSocks4ProxyHandshake() throws Exception {
+        try (ServerSocket proxyServer = new ServerSocket(0)) {
+            int proxyPort = proxyServer.getLocalPort();
+            CountDownLatch handshakeDone = new CountDownLatch(1);
+
+            Thread serverThread = new Thread(() -> {
+                try (Socket clientSock = proxyServer.accept()) {
+                    InputStream in = clientSock.getInputStream();
+                    OutputStream out = clientSock.getOutputStream();
+
+                    // Read SOCKS4 request header
+                    byte[] req = new byte[8];
+                    in.read(req);
+                    assertEquals(0x04, req[0]); // SOCKS4
+                    assertEquals(0x01, req[1]); // CONNECT
+
+                    // Read null-terminated username
+                    ByteArrayOutputStream userBuf = new ByteArrayOutputStream();
+                    int b;
+                    while ((b = in.read()) != 0 && b != -1) {
+                        userBuf.write(b);
+                    }
+                    assertEquals("user4", new String(userBuf.toByteArray()));
+
+                    // Reply 0x00 0x5A (Request granted)
+                    byte[] resp = new byte[] { 0x00, 0x5A, 0x00, 0x17, 127, 0, 0, 1 };
+                    out.write(resp);
+                    out.flush();
+                    handshakeDone.countDown();
+
+                    while (in.read() != -1) {}
+                } catch (Exception ignored) {}
+            });
+            serverThread.setDaemon(true);
+            serverThread.start();
+
+            ConnectionConfig config = new ConnectionConfig("127.0.0.1", 23);
+            config.setProxy(ConnectionConfig.ProxyType.SOCKS4, "127.0.0.1", proxyPort, "user4", null);
+            config.setConnectTimeoutMs(5000);
+
+            TelnetFSM fsm = new TelnetFSM(config, new haus.nightmare.lib3270j.screen.ScreenBuffer(TerminalModel.IBM_3279_4, new haus.nightmare.lib3270j.charset.EbcdicTranslator()), null);
+            TelnetConnection connection = new TelnetConnection(config, fsm);
+
+            connection.connect();
+            assertTrue(connection.isConnected());
+            assertTrue(handshakeDone.await(3, TimeUnit.SECONDS));
+
+            connection.disconnect();
+        }
+    }
+
+    @Test
+    public void testSocks5ProxyHandshakeWithAuth() throws Exception {
+        try (ServerSocket proxyServer = new ServerSocket(0)) {
+            int proxyPort = proxyServer.getLocalPort();
+            CountDownLatch handshakeDone = new CountDownLatch(1);
+
+            Thread serverThread = new Thread(() -> {
+                try (Socket clientSock = proxyServer.accept()) {
+                    InputStream in = clientSock.getInputStream();
+                    OutputStream out = clientSock.getOutputStream();
+
+                    // 1. Read method selection
+                    int ver = in.read();
+                    int nmethods = in.read();
+                    byte[] methods = new byte[nmethods];
+                    in.read(methods);
+                    assertEquals(0x05, ver);
+
+                    // Select USER_PASS (0x02)
+                    out.write(new byte[] { 0x05, 0x02 });
+                    out.flush();
+
+                    // 2. Read auth request (RFC 1929)
+                    int authVer = in.read();
+                    int ulen = in.read();
+                    byte[] u = new byte[ulen];
+                    in.read(u);
+                    int plen = in.read();
+                    byte[] p = new byte[plen];
+                    in.read(p);
+
+                    assertEquals(1, authVer);
+                    assertEquals("admin", new String(u));
+                    assertEquals("pass123", new String(p));
+
+                    // Auth success: 0x01 0x00
+                    out.write(new byte[] { 0x01, 0x00 });
+                    out.flush();
+
+                    // 3. Read connect command
+                    byte[] cmd = new byte[4];
+                    in.read(cmd);
+                    assertEquals(0x05, cmd[0]);
+                    assertEquals(0x01, cmd[1]); // CONNECT
+                    int atyp = cmd[3];
+                    if (atyp == 0x03) { // Domain name
+                        int dlen = in.read();
+                        byte[] d = new byte[dlen];
+                        in.read(d);
+                    } else if (atyp == 0x01) { // IPv4
+                        in.read(new byte[4]);
+                    }
+                    in.read(new byte[2]); // Port
+
+                    // Reply success: 0x05 0x00 0x00 0x01 127.0.0.1:port
+                    out.write(new byte[] { 0x05, 0x00, 0x00, 0x01, 127, 0, 0, 1, 0, 23 });
+                    out.flush();
+                    handshakeDone.countDown();
+
+                    while (in.read() != -1) {}
+                } catch (Exception ignored) {}
+            });
+            serverThread.setDaemon(true);
+            serverThread.start();
+
+            ConnectionConfig config = new ConnectionConfig("mvs.corp.local", 23);
+            config.setProxy(ConnectionConfig.ProxyType.SOCKS5, "127.0.0.1", proxyPort, "admin", "pass123");
+            config.setConnectTimeoutMs(5000);
+
+            TelnetFSM fsm = new TelnetFSM(config, new haus.nightmare.lib3270j.screen.ScreenBuffer(TerminalModel.IBM_3279_4, new haus.nightmare.lib3270j.charset.EbcdicTranslator()), null);
+            TelnetConnection connection = new TelnetConnection(config, fsm);
+
+            connection.connect();
+            assertTrue(connection.isConnected());
+            assertTrue(handshakeDone.await(3, TimeUnit.SECONDS));
+
+            connection.disconnect();
+        }
+    }
+}
diff --git a/lib3270j/src/test/java/haus/nightmare/lib3270j/telnet/TelnetFSMPhase1FullTest.java b/lib3270j/src/test/java/haus/nightmare/lib3270j/telnet/TelnetFSMPhase1FullTest.java
new file mode 100644
index 0000000..e6f50d0
--- /dev/null
+++ b/lib3270j/src/test/java/haus/nightmare/lib3270j/telnet/TelnetFSMPhase1FullTest.java
@@ -0,0 +1,346 @@
+package haus.nightmare.lib3270j.telnet;
+
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
+import haus.nightmare.lib3270j.ConnectionConfig;
+import haus.nightmare.lib3270j.ConnectionState;
+import haus.nightmare.lib3270j.TerminalModel;
+import haus.nightmare.lib3270j.charset.EbcdicTranslator;
+import haus.nightmare.lib3270j.datastream.DataStreamProcessor;
+import haus.nightmare.lib3270j.input.InputProcessor;
+import haus.nightmare.lib3270j.listener.SCSInboundListener;
+import haus.nightmare.lib3270j.protocol.TelnetConstants;
+import haus.nightmare.lib3270j.protocol.TN3270EConstants;
+import haus.nightmare.lib3270j.screen.ScreenBuffer;
+
+import java.io.ByteArrayOutputStream;
+import java.io.IOException;
+import java.util.ArrayList;
+import java.util.List;
+import java.util.Properties;
+
+import static org.junit.jupiter.api.Assertions.*;
+import static haus.nightmare.lib3270j.protocol.TelnetConstants.*;
+import static haus.nightmare.lib3270j.protocol.TN3270EConstants.*;
+
+public class TelnetFSMPhase1FullTest {
+
+    private ConnectionConfig config;
+    private ScreenBuffer screenBuffer;
+    private DataStreamProcessor dsProcessor;
+    private InputProcessor inputProcessor;
+    private TelnetFSM fsm;
+    private MockConnection connection;
+    private EbcdicTranslator translator;
+
+    private static class MockConnection extends TelnetConnection {
+        final List<byte[]> sentData = new ArrayList<>();
+        boolean tlsUpgraded = false;
+
+        MockConnection(ConnectionConfig config, TelnetFSM fsm) {
+            super(config, fsm);
+        }
+
+        @Override
+        public synchronized void sendRaw(byte[] data) {
+            sentData.add(data.clone());
+        }
+
+        @Override
+        public synchronized void sendRaw(byte[] data, int offset, int length) {
+            byte[] b = new byte[length];
+            System.arraycopy(data, offset, b, 0, length);
+            sentData.add(b);
+        }
+
+        @Override
+        public synchronized void upgradeToTls() throws IOException {
+            tlsUpgraded = true;
+        }
+    }
+
+    @BeforeEach
+    public void setup() {
+        translator = new EbcdicTranslator();
+        config = new ConnectionConfig("localhost", 23, TerminalModel.IBM_3279_4);
+        screenBuffer = new ScreenBuffer(TerminalModel.IBM_3279_4, translator);
+        dsProcessor = new DataStreamProcessor(screenBuffer, translator);
+        fsm = new TelnetFSM(config, screenBuffer, dsProcessor);
+        inputProcessor = new InputProcessor(screenBuffer, translator, fsm);
+        dsProcessor.setInputProcessor(inputProcessor);
+        connection = new MockConnection(config, fsm);
+        fsm.setConnection(connection);
+    }
+
+    private void feedBytes(int... bytes) {
+        for (int b : bytes) {
+            fsm.feedByte(b & 0xFF);
+        }
+    }
+
+    @Test
+    public void testSendTn3270eResponseAndHoD5ByteSignature() {
+        connection.sentData.clear();
+
+        // 1. Standard 6-byte RFC 2355 response
+        fsm.sendTn3270eResponse((byte) RSF_POSITIVE_RESPONSE, (byte) POS_DEVICE_END, 0x1234);
+        assertEquals(1, connection.sentData.size());
+        byte[] resp6 = connection.sentData.get(0);
+        assertEquals(6 + 2, resp6.length); // 6 bytes header/trailer + IAC EOR
+        assertEquals(DT_RESPONSE, resp6[0] & 0xFF);
+        assertEquals(0, resp6[1] & 0xFF);
+        assertEquals(RSF_POSITIVE_RESPONSE, resp6[2] & 0xFF);
+        assertEquals(0x12, resp6[3] & 0xFF);
+        assertEquals(0x34, resp6[4] & 0xFF);
+        assertEquals(POS_DEVICE_END, resp6[5] & 0xFF);
+        assertEquals(IAC, resp6[6] & 0xFF);
+        assertEquals(EOR, resp6[7] & 0xFF);
+
+        // 2. HoD 5-byte send_response
+        connection.sentData.clear();
+        fsm.send_response((short) 0, (short) RSF_POSITIVE_RESPONSE, 0x5678);
+        assertEquals(1, connection.sentData.size());
+        byte[] resp5 = connection.sentData.get(0);
+        assertEquals(5 + 2, resp5.length); // 5 bytes + IAC EOR
+        assertEquals(DT_RESPONSE, resp5[0] & 0xFF);
+        assertEquals(0, resp5[1] & 0xFF);
+        assertEquals(RSF_POSITIVE_RESPONSE, resp5[2] & 0xFF);
+        assertEquals(0x56, resp5[3] & 0xFF);
+        assertEquals(0x78, resp5[4] & 0xFF);
+    }
+
+    @Test
+    public void testStartTlsOption46NegotiationAndElevation() {
+        config.setStartTlsEnabled(true);
+        fsm.onConnected();
+        connection.sentData.clear();
+
+        // Server sends DO STARTTLS (Option 46)
+        feedBytes(IAC, DO, TELOPT_STARTTLS);
+
+        // Client must reply WILL STARTTLS
+        assertEquals(1, connection.sentData.size());
+        assertArrayEquals(new byte[] { (byte) IAC, (byte) WILL, (byte) TELOPT_STARTTLS }, connection.sentData.get(0));
+        assertTrue(fsm.getMyOpts()[TELOPT_STARTTLS]);
+        connection.sentData.clear();
+
+        // Server sends SB STARTTLS 1 (TLS_FOLLOWS) SE
+        feedBytes(IAC, SB, TELOPT_STARTTLS, TLS_FOLLOWS, IAC, SE);
+
+        // Connection must have been upgraded to TLS
+        assertTrue(connection.tlsUpgraded, "Expected upgradeToTls() to be invoked on STARTTLS_FOLLOWS");
+    }
+
+    @Test
+    public void testRfc1572NewEnvironEmptySendReturnsAllVariables() {
+        config.setEnvironmentVariable("USER", "MAINFRAME_USER");
+        config.setEnvironmentVariable("SYSTEMTYPE", "MVS");
+        config.setUserVariable("IBM_EXPRESS_LOGON", "CERT_AUTH_ENABLED");
+
+        fsm.onConnected();
+        connection.sentData.clear();
+
+        // Server sends DO NEW_ENVIRON
+        feedBytes(IAC, DO, TELOPT_NEW_ENVIRON);
+        assertEquals(1, connection.sentData.size());
+        assertArrayEquals(new byte[] { (byte) IAC, (byte) WILL, (byte) TELOPT_NEW_ENVIRON }, connection.sentData.get(0));
+        connection.sentData.clear();
+
+        // Server sends SB NEW-ENVIRON SEND SE (empty query -> all variables)
+        feedBytes(IAC, SB, TELOPT_NEW_ENVIRON, TELQUAL_SEND, IAC, SE);
+
+        assertEquals(1, connection.sentData.size());
+        byte[] pkt = connection.sentData.get(0);
+        assertTrue(pkt.length >= 6);
+        assertEquals(IAC, pkt[0] & 0xFF);
+        assertEquals(SB, pkt[1] & 0xFF);
+        assertEquals(TELOPT_NEW_ENVIRON, pkt[2] & 0xFF);
+        assertEquals(TELQUAL_IS, pkt[3] & 0xFF);
+
+        String pktStr = new String(pkt);
+        assertTrue(pktStr.contains("USER"));
+        assertTrue(pktStr.contains("MAINFRAME_USER"));
+        assertTrue(pktStr.contains("SYSTEMTYPE"));
+        assertTrue(pktStr.contains("MVS"));
+        assertTrue(pktStr.contains("IBM_EXPRESS_LOGON"));
+        assertTrue(pktStr.contains("CERT_AUTH_ENABLED"));
+    }
+
+    @Test
+    public void testRfc1572NewEnvironSelectiveSend() throws Exception {
+        config.setEnvironmentVariable("USER", "ALICE");
+        config.setEnvironmentVariable("JOB", "DAILY_REPORT");
+        config.setUserVariable("SEC_TOKEN", "XYZ123");
+
+        fsm.onConnected();
+        connection.sentData.clear();
+
+        // Server sends SB NEW-ENVIRON SEND VAR "USER" USERVAR "SEC_TOKEN" SE
+        ByteArrayOutputStream query = new ByteArrayOutputStream();
+        query.write(IAC);
+        query.write(SB);
+        query.write(TELOPT_NEW_ENVIRON);
+        query.write(TELQUAL_SEND);
+        query.write(TELOBJ_VAR);
+        query.write("USER".getBytes());
+        query.write(TELOBJ_USERVAR);
+        query.write("SEC_TOKEN".getBytes());
+        query.write(IAC);
+        query.write(SE);
+
+        for (byte b : query.toByteArray()) {
+            fsm.feedByte(b & 0xFF);
+        }
+
+        assertEquals(1, connection.sentData.size());
+        String respStr = new String(connection.sentData.get(0));
+        assertTrue(respStr.contains("USER"));
+        assertTrue(respStr.contains("ALICE"));
+        assertTrue(respStr.contains("SEC_TOKEN"));
+        assertTrue(respStr.contains("XYZ123"));
+        assertFalse(respStr.contains("JOB"), "Unrequested variable JOB should not be sent");
+    }
+
+    @Test
+    public void testSendNewEnvironmentVariablesFromProperties() {
+        Properties props = new Properties();
+        props.setProperty("VAR_TEST", "VAL1");
+        props.setProperty("USERVAR_TOKEN", "VAL2");
+
+        connection.sentData.clear();
+        fsm.sendNewEnvironmentVariables(props);
+
+        assertEquals(1, connection.sentData.size());
+        byte[] pkt = connection.sentData.get(0);
+        assertEquals(IAC, pkt[0] & 0xFF);
+        assertEquals(SB, pkt[1] & 0xFF);
+        assertEquals(TELOPT_NEW_ENVIRON, pkt[2] & 0xFF);
+        assertEquals(TELQUAL_IS, pkt[3] & 0xFF);
+
+        String pktStr = new String(pkt);
+        assertTrue(pktStr.contains("VAR_TEST"));
+        assertTrue(pktStr.contains("VAL1"));
+        assertTrue(pktStr.contains("USERVAR_TOKEN"));
+        assertTrue(pktStr.contains("VAL2"));
+    }
+
+    @Test
+    public void testInboundSCSDataHandlingAndAutoPositiveResponse() throws Exception {
+        config.setTn3270eEnabled(true);
+        fsm.onConnected();
+
+        // Negotiate TN3270E with RESPONSES and SCS_CTL_CODES
+        feedBytes(IAC, DO, TELOPT_TN3270E);
+        feedBytes(IAC, SB, TELOPT_TN3270E, OP_SEND, OP_DEVICE_TYPE, IAC, SE);
+        byte[] devTypeIs = new byte[]{
+            (byte) IAC, (byte) SB, (byte) TELOPT_TN3270E,
+            0x02, 0x04, 'I', 'B', 'M', '-', '3', '2', '8', '7', '-', '1',
+            (byte) IAC, (byte) SE
+        };
+        for (byte b : devTypeIs) fsm.feedByte(b & 0xFF);
+
+        byte[] funcsReq = new byte[]{
+            (byte) IAC, (byte) SB, (byte) TELOPT_TN3270E,
+            (byte) OP_FUNCTIONS, (byte) OP_REQUEST,
+            (byte) FUNC_BIND_IMAGE, (byte) FUNC_RESPONSES, (byte) FUNC_SCS_CTL_CODES,
+            (byte) IAC, (byte) SE
+        };
+        for (byte b : funcsReq) fsm.feedByte(b & 0xFF);
+
+        List<byte[]> scsReceived = new ArrayList<>();
+        fsm.addSCSInboundListener(new SCSInboundListener() {
+            @Override
+            public void onSCSDataReceived(byte[] data, int offset, int length) {
+                byte[] copy = new byte[length];
+                System.arraycopy(data, offset, copy, 0, length);
+                scsReceived.add(copy);
+            }
+        });
+
+        connection.sentData.clear();
+
+        // Send DT_SCS_DATA (0x01) record with ALWAYS_RESPONSE
+        int seq = 0x00A1;
+        byte[] scsPayload = new byte[] { 0x15, 0x2B, (byte) 0xD2, 0x04, 0x15 }; // SCS orders
+        ByteArrayOutputStream scsRecord = new ByteArrayOutputStream();
+        scsRecord.write(DT_SCS_DATA);
+        scsRecord.write(0x00); // Request flag
+        scsRecord.write(RSF_ALWAYS_RESPONSE);
+        scsRecord.write((seq >> 8) & 0xFF);
+        scsRecord.write(seq & 0xFF);
+        scsRecord.write(scsPayload);
+        scsRecord.write(IAC);
+        scsRecord.write(EOR);
+
+        for (byte b : scsRecord.toByteArray()) {
+            fsm.feedByte(b & 0xFF);
+        }
+
+        // Verify SCS listener was notified with exact payload
+        assertEquals(1, scsReceived.size());
+        assertArrayEquals(scsPayload, scsReceived.get(0));
+
+        // Verify positive response was sent
+        boolean foundPositive = false;
+        for (byte[] pkt : connection.sentData) {
+            if (pkt.length >= 8 &&
+                (pkt[0] & 0xFF) == DT_RESPONSE &&
+                (pkt[2] & 0xFF) == RSF_POSITIVE_RESPONSE &&
+                ((((pkt[3] & 0xFF) << 8) | (pkt[4] & 0xFF)) == seq) &&
+                (pkt[5] & 0xFF) == POS_DEVICE_END) {
+                foundPositive = true;
+            }
+        }
+        assertTrue(foundPositive, "Expected positive response for DT_SCS_DATA with RSF_ALWAYS_RESPONSE");
+    }
+
+    @Test
+    public void testProcessSysReqMethod() {
+        config.setTn3270eEnabled(true);
+        fsm.onConnected();
+
+        // Negotiate TN3270E
+        feedBytes(IAC, DO, TELOPT_TN3270E);
+        feedBytes(IAC, SB, TELOPT_TN3270E, OP_SEND, OP_DEVICE_TYPE, IAC, SE);
+        byte[] devTypeIs = new byte[]{
+            (byte) IAC, (byte) SB, (byte) TELOPT_TN3270E,
+            0x02, 0x04, 'I', 'B', 'M', '-', '3', '2', '7', '9', '-', '4', '-', 'E',
+            (byte) IAC, (byte) SE
+        };
+        for (byte b : devTypeIs) fsm.feedByte(b & 0xFF);
+        byte[] funcsReq = new byte[]{
+            (byte) IAC, (byte) SB, (byte) TELOPT_TN3270E,
+            (byte) OP_FUNCTIONS, (byte) OP_REQUEST,
+            (byte) FUNC_BIND_IMAGE, (byte) FUNC_RESPONSES, (byte) FUNC_SYSREQ,
+            (byte) IAC, (byte) SE
+        };
+        for (byte b : funcsReq) fsm.feedByte(b & 0xFF);
+
+        // Bind session
+        byte[] bindPacket = new byte[EH_SIZE + 35];
+        bindPacket[0] = DT_BIND_IMAGE;
+        bindPacket[1] = 0; bindPacket[2] = 0; bindPacket[3] = 0; bindPacket[4] = 1;
+        bindPacket[EH_SIZE + 24] = 0x02;
+        ByteArrayOutputStream bStream = new ByteArrayOutputStream();
+        bStream.write(bindPacket, 0, bindPacket.length);
+        bStream.write(IAC);
+        bStream.write(EOR);
+        for (byte b : bStream.toByteArray()) fsm.feedByte(b & 0xFF);
+
+        assertEquals(ConnectionState.CONNECTED_TN3270E, fsm.getConnectionState());
+        connection.sentData.clear();
+
+        // Call processSysReq()
+        fsm.processSysReq();
+
+        // State changes to CONNECTED_SSCP and IAC AO sent
+        assertEquals(ConnectionState.CONNECTED_SSCP, fsm.getConnectionState());
+        boolean foundAo = false;
+        for (byte[] pkt : connection.sentData) {
+            if (pkt.length == 2 && (pkt[0] & 0xFF) == IAC && (pkt[1] & 0xFF) == AO) {
+                foundAo = true;
+            }
+        }
+        assertTrue(foundAo, "Expected IAC AO out-of-band telnet abort");
+    }
+}
diff --git a/lib3270j/src/test/java/haus/nightmare/lib3270j/telnet/TelnetFSMTest.java b/lib3270j/src/test/java/haus/nightmare/lib3270j/telnet/TelnetFSMTest.java
index d5ed696..9038d14 100644
--- a/lib3270j/src/test/java/haus/nightmare/lib3270j/telnet/TelnetFSMTest.java
+++ b/lib3270j/src/test/java/haus/nightmare/lib3270j/telnet/TelnetFSMTest.java
@@ -50,6 +50,9 @@ public class TelnetFSMTest {
         screenBuffer = new ScreenBuffer(TerminalModel.IBM_3279_4, new EbcdicTranslator());
         dsProcessor = new DataStreamProcessor(screenBuffer, new EbcdicTranslator());
         fsm = new TelnetFSM(config, screenBuffer, dsProcessor);
+        haus.nightmare.lib3270j.input.InputProcessor inputProcessor =
+            new haus.nightmare.lib3270j.input.InputProcessor(screenBuffer, new EbcdicTranslator(), fsm);
+        dsProcessor.setInputProcessor(inputProcessor);
         connection = new MockConnection(config, fsm);
         fsm.setConnection(connection);
     }
@@ -294,4 +297,212 @@ public class TelnetFSMTest {
         String resp3 = new String(lastPkt, 4, lastPkt.length - 6);
         assertEquals("IBM-3278-4-E", resp3);
     }
+
+    @Test
+    public void testTn3270eNvtInboundAndOutbound() throws Exception {
+        fsm.onConnected();
+        connection.sentData.clear();
+
+        // Negotiate TN3270E without BIND-IMAGE
+        feedBytes(TelnetConstants.IAC, TelnetConstants.DO, TelnetConstants.TELOPT_TN3270E);
+        feedBytes(TelnetConstants.IAC, TelnetConstants.WILL, TelnetConstants.TELOPT_TN3270E);
+
+        // Host sends DEVICE-TYPE SEND
+        feedBytes(TelnetConstants.IAC, TelnetConstants.SB, TelnetConstants.TELOPT_TN3270E,
+                  0x08, 0x01, TelnetConstants.IAC, TelnetConstants.SE);
+
+        // Host sends DEVICE-TYPE IS IBM-3279-4-E
+        feedBytes(TelnetConstants.IAC, TelnetConstants.SB, TelnetConstants.TELOPT_TN3270E,
+                  0x02, 0x04, 'I', 'B', 'M', '-', '3', '2', '7', '9', '-', '4', '-', 'E',
+                  TelnetConstants.IAC, TelnetConstants.SE);
+
+        // Host sends FUNCTIONS IS (no BIND-IMAGE)
+        feedBytes(TelnetConstants.IAC, TelnetConstants.SB, TelnetConstants.TELOPT_TN3270E,
+                  0x03, 0x04, TelnetConstants.IAC, TelnetConstants.SE);
+
+        assertEquals(ConnectionState.CONNECTED_TN3270E, fsm.getConnectionState());
+
+        // Host sends DT_NVT_DATA (0x05) record with text "PROMPT: "
+        byte[] nvtRecord = {
+            0x05, // DT_NVT_DATA
+            0x00, // request flag
+            0x00, // response flag
+            0x00, 0x01, // seq 1
+            'P', 'R', 'O', 'M', 'P', 'T', ':', ' ',
+            (byte) TelnetConstants.IAC, (byte) TelnetConstants.EOR
+        };
+        for (byte b : nvtRecord) {
+            fsm.feedByte(b & 0xFF);
+        }
+
+        // FSM must transition to CONNECTED_E_NVT
+        assertEquals(ConnectionState.CONNECTED_E_NVT, fsm.getConnectionState());
+        assertTrue(fsm.getConnectionState().isNvt());
+
+        // Verify screen buffer contains the NVT text
+        assertEquals('P', screenBuffer.getCell(0).ucs4);
+        assertEquals('R', screenBuffer.getCell(1).ucs4);
+        assertEquals('O', screenBuffer.getCell(2).ucs4);
+        assertEquals('M', screenBuffer.getCell(3).ucs4);
+        assertEquals('P', screenBuffer.getCell(4).ucs4);
+        assertEquals('T', screenBuffer.getCell(5).ucs4);
+        assertEquals(':', screenBuffer.getCell(6).ucs4);
+        assertEquals(' ', screenBuffer.getCell(7).ucs4);
+        assertEquals(8, screenBuffer.getCursorAddress());
+
+        // Test Outbound NVT sending in TN3270E mode
+        connection.sentData.clear();
+        fsm.sendNVTString("OK\n");
+
+        assertFalse(connection.sentData.isEmpty());
+        byte[] sentPkt = connection.sentData.get(connection.sentData.size() - 1);
+
+        // Sent packet should be TN3270E record: 5-byte header + "OK\r\n" + IAC EOR
+        assertEquals(5 + 4 + 2, sentPkt.length);
+        assertEquals(0x05, sentPkt[0]); // DT_NVT_DATA
+        assertEquals('O', sentPkt[5]);
+        assertEquals('K', sentPkt[6]);
+        assertEquals('\r', sentPkt[7]);
+        assertEquals('\n', sentPkt[8]);
+        assertEquals((byte) TelnetConstants.IAC, sentPkt[9]);
+        assertEquals((byte) TelnetConstants.EOR, sentPkt[10]);
+    }
+
+    @Test
+    public void testPlainTelnetNvtStreamingAndLocalEcho() throws Exception {
+        fsm.onConnected();
+        config.setNvtLocalEcho(true);
+
+        // Receiving raw bytes in TELNET_PENDING automatically transitions to CONNECTED_NVT
+        feedBytes('L', 'O', 'G', 'I', 'N', '>');
+        assertEquals(ConnectionState.CONNECTED_NVT, fsm.getConnectionState());
+        assertEquals('L', screenBuffer.getCell(0).ucs4);
+        assertEquals('>', screenBuffer.getCell(5).ucs4);
+
+        // Sending NVT data with local echo enabled
+        connection.sentData.clear();
+        fsm.sendNVTString("TEST");
+
+        // Raw bytes sent over TCP
+        assertEquals(1, connection.sentData.size());
+        byte[] sent = connection.sentData.get(0);
+        assertArrayEquals("TEST".getBytes(), sent);
+
+        // Local echo placed "TEST" on screen starting at address 6
+        assertEquals('T', screenBuffer.getCell(6).ucs4);
+        assertEquals('E', screenBuffer.getCell(7).ucs4);
+        assertEquals('S', screenBuffer.getCell(8).ucs4);
+        assertEquals('T', screenBuffer.getCell(9).ucs4);
+        assertEquals(10, screenBuffer.getCursorAddress());
+    }
+
+    @Test
+    public void testVmConmode3270TransitionTn3270e() throws Exception {
+        fsm.onConnected();
+        connection.sentData.clear();
+
+        // 1. Negotiate TN3270E
+        feedBytes(TelnetConstants.IAC, TelnetConstants.DO, TelnetConstants.TELOPT_TN3270E);
+        feedBytes(TelnetConstants.IAC, TelnetConstants.WILL, TelnetConstants.TELOPT_TN3270E);
+        feedBytes(TelnetConstants.IAC, TelnetConstants.SB, TelnetConstants.TELOPT_TN3270E,
+                  0x08, 0x01, TelnetConstants.IAC, TelnetConstants.SE);
+        feedBytes(TelnetConstants.IAC, TelnetConstants.SB, TelnetConstants.TELOPT_TN3270E,
+                  0x02, 0x04, 'I', 'B', 'M', '-', '3', '2', '7', '9', '-', '4', '-', 'E',
+                  TelnetConstants.IAC, TelnetConstants.SE);
+        feedBytes(TelnetConstants.IAC, TelnetConstants.SB, TelnetConstants.TELOPT_TN3270E,
+                  0x03, 0x04, TelnetConstants.IAC, TelnetConstants.SE);
+
+        assertEquals(ConnectionState.CONNECTED_TN3270E, fsm.getConnectionState());
+
+        // 2. VM console in line-mode sends DT_NVT_DATA (e.g. CP prompt)
+        byte[] nvtRecord = {
+            0x05, 0x00, 0x00, 0x00, 0x01,
+            'C', 'P', ' ', 'R', 'E', 'A', 'D', 'Y', '\r', '\n',
+            (byte) TelnetConstants.IAC, (byte) TelnetConstants.EOR
+        };
+        for (byte b : nvtRecord) fsm.feedByte(b & 0xFF);
+
+        assertEquals(ConnectionState.CONNECTED_E_NVT, fsm.getConnectionState());
+        assertEquals(TelnetFSM.TN3270ESubmode.E_NVT, fsm.getTn3270eSubmode());
+
+        // 3. VM executes "cp term conmode 3270" and sends 3270 full screen (DT_3270_DATA)
+        EbcdicTranslator trans = new EbcdicTranslator();
+        String banner = "z/VM 3270 FULLSCREEN";
+        byte[] stream3270 = new byte[5 + 5 + banner.length() + 2];
+        // 5-byte TN3270E header
+        stream3270[0] = 0x00; // DT_3270_DATA
+        stream3270[1] = 0x00;
+        stream3270[2] = 0x00;
+        stream3270[3] = 0x00; stream3270[4] = 0x02; // seq 2
+        // 3270 Orders
+        stream3270[5] = (byte) 0xF5; // EraseWrite
+        stream3270[6] = (byte) 0xC3; // WCC
+        stream3270[7] = 0x11;        // SBA
+        stream3270[8] = 0x40; stream3270[9] = 0x40; // pos 0
+        for (int i = 0; i < banner.length(); i++) {
+            stream3270[10 + i] = (byte) trans.unicodeToEbcdic(banner.charAt(i));
+        }
+        stream3270[stream3270.length - 2] = (byte) TelnetConstants.IAC;
+        stream3270[stream3270.length - 1] = (byte) TelnetConstants.EOR;
+
+        for (byte b : stream3270) fsm.feedByte(b & 0xFF);
+
+        // Verify transition from E_NVT to E_3270 (CONNECTED_TN3270E)
+        assertEquals(ConnectionState.CONNECTED_TN3270E, fsm.getConnectionState());
+        assertEquals(TelnetFSM.TN3270ESubmode.E_3270, fsm.getTn3270eSubmode());
+        assertFalse(fsm.getConnectionState().isNvt());
+
+        // Verify screen displays 3270 content
+        assertEquals('z', trans.ebcdicToUnicode(screenBuffer.getCellEC(0)));
+        assertEquals('/', trans.ebcdicToUnicode(screenBuffer.getCellEC(1)));
+        assertEquals('V', trans.ebcdicToUnicode(screenBuffer.getCellEC(2)));
+        assertEquals('M', trans.ebcdicToUnicode(screenBuffer.getCellEC(3)));
+
+        // 4. Outbound 3270 AID transmission should now use DT_3270_DATA
+        connection.sentData.clear();
+        dsProcessor.getInputProcessor().sendAid(0x7D);
+
+        assertFalse(connection.sentData.isEmpty());
+        byte[] sentAid = connection.sentData.get(connection.sentData.size() - 1);
+        assertEquals(0x00, sentAid[0]); // DT_3270_DATA header
+        assertEquals((byte) 0x7D, sentAid[5]); // Enter AID code
+    }
+
+    @Test
+    public void testVmConmode3270TransitionPlainTelnet() throws Exception {
+        fsm.onConnected();
+        config.setTn3270eEnabled(false);
+
+        // 1. Connected in line-mode (NVT)
+        feedBytes('C', 'P', '>');
+        assertEquals(ConnectionState.CONNECTED_NVT, fsm.getConnectionState());
+
+        // 2. VM sends BINARY and EOR options upon CONMODE 3270
+        feedBytes(TelnetConstants.IAC, TelnetConstants.DO, TelnetConstants.TELOPT_BINARY);
+        feedBytes(TelnetConstants.IAC, TelnetConstants.WILL, TelnetConstants.TELOPT_BINARY);
+        feedBytes(TelnetConstants.IAC, TelnetConstants.DO, TelnetConstants.TELOPT_EOR);
+        feedBytes(TelnetConstants.IAC, TelnetConstants.WILL, TelnetConstants.TELOPT_EOR);
+
+        // Verify transition to CONNECTED_3270
+        assertEquals(ConnectionState.CONNECTED_3270, fsm.getConnectionState());
+
+        // 3. VM sends 3270 data stream
+        EbcdicTranslator trans = new EbcdicTranslator();
+        String msg = "VM 3270";
+        byte[] rawStream = new byte[5 + msg.length() + 2];
+        rawStream[0] = (byte) 0xF5; // EraseWrite
+        rawStream[1] = (byte) 0xC3; // WCC
+        rawStream[2] = 0x11;        // SBA
+        rawStream[3] = 0x40; rawStream[4] = 0x40;
+        for (int i = 0; i < msg.length(); i++) {
+            rawStream[5 + i] = (byte) trans.unicodeToEbcdic(msg.charAt(i));
+        }
+        rawStream[rawStream.length - 2] = (byte) TelnetConstants.IAC;
+        rawStream[rawStream.length - 1] = (byte) TelnetConstants.EOR;
+
+        for (byte b : rawStream) fsm.feedByte(b & 0xFF);
+
+        assertEquals('V', trans.ebcdicToUnicode(screenBuffer.getCellEC(0)));
+        assertEquals('M', trans.ebcdicToUnicode(screenBuffer.getCellEC(1)));
+    }
 }