Add dark mode and simple theming support to GUI

- Add DARK_THEME stylesheet alongside existing LIGHT_THEME
- Add load_theme() function to load themes by name
- Support custom themes via ~/.cmdforge/theme.qss
- Add View menu with Theme submenu for switching themes
- Persist theme choice in QSettings across sessions
- Update META_TOOLS.md to reflect implemented dependency commands

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

olddocs/META_TOOLS.md

@@ -1,8 +1,11 @@
 # Meta-Tools: Tools That Call Other Tools
 
 > **Document Status (January 2026)**: The `tool` step type is implemented and works as described.
-> The CLI dependency commands (`cmdforge install --deps`, `cmdforge check`) are not yet implemented.
+> The CLI dependency commands are now implemented:
-> Tools can still use `tool` steps, but dependency resolution is manual.
+> - `cmdforge check <tool>` - Check if dependencies are satisfied
+> - `cmdforge install` - Install dependencies from cmdforge.yaml manifest
+> - `cmdforge add <owner/name>` - Add a tool to project dependencies
+> - `--auto-install` flag on tool execution for automatic dependency installation
 
 Meta-tools are CmdForge tools that can invoke other tools as steps in their workflow. This enables powerful composition and reuse of existing tools.
 

src/cmdforge/gui/main_window.py

@@ -6,9 +6,9 @@ from PySide6.QtWidgets import (
     QStatusBar, QLabel, QSplitter, QMenuBar, QMenu
 )
 from PySide6.QtCore import Qt, QSize, QSettings, QTimer
-from PySide6.QtGui import QIcon, QFont, QShortcut, QKeySequence, QAction
+from PySide6.QtGui import QIcon, QFont, QShortcut, QKeySequence, QAction, QActionGroup
 
-from .styles import STYLESHEET
+from .styles import load_theme, get_available_themes, get_custom_theme_path
 
 
 class MainWindow(QMainWindow):
@@ -20,12 +20,13 @@ class MainWindow(QMainWindow):
         self.setMinimumSize(1000, 700)
         self.resize(1200, 800)
 
-        # Apply stylesheet
-        self.setStyleSheet(STYLESHEET)
-
         # Settings for persistence
         self._settings = QSettings("CmdForge", "CmdForge")
 
+        # Load and apply theme
+        self._current_theme = self._settings.value("theme", "light")
+        self._apply_theme(self._current_theme)
+
         # Central widget
         central = QWidget()
         self.setCentralWidget(central)
@@ -235,10 +236,54 @@ class MainWindow(QMainWindow):
         shortcut_help = QShortcut(QKeySequence("F1"), self)
         shortcut_help.activated.connect(self._show_getting_started)
 
+    def _apply_theme(self, theme_name: str):
+        """Apply a theme to the application."""
+        stylesheet = load_theme(theme_name)
+        self.setStyleSheet(stylesheet)
+        self._current_theme = theme_name
+        self._settings.setValue("theme", theme_name)
+
     def _setup_menu_bar(self):
-        """Set up the menu bar with Help menu."""
+        """Set up the menu bar with View and Help menus."""
         menubar = self.menuBar()
 
+        # View menu
+        view_menu = menubar.addMenu("&View")
+
+        # Theme submenu
+        theme_menu = view_menu.addMenu("&Theme")
+        theme_group = QActionGroup(self)
+        theme_group.setExclusive(True)
+
+        # Add theme options
+        for theme_name in get_available_themes():
+            display_name = theme_name.capitalize()
+            if theme_name == "custom":
+                display_name = f"Custom ({get_custom_theme_path().name})"
+
+            action = QAction(display_name, self)
+            action.setCheckable(True)
+            action.setChecked(theme_name == self._current_theme)
+            action.setData(theme_name)
+            # Use default argument to capture theme_name by value
+            action.triggered.connect(lambda checked=False, t=theme_name: self._apply_theme(t))
+            theme_group.addAction(action)
+            theme_menu.addAction(action)
+
+        # Add hint about custom themes
+        theme_menu.addSeparator()
+        hint_action = QAction(f"Custom: ~/.cmdforge/theme.qss", self)
+        hint_action.setEnabled(False)
+        theme_menu.addAction(hint_action)
+
+        view_menu.addSeparator()
+
+        # Refresh action
+        action_refresh = QAction("&Refresh", self)
+        action_refresh.setShortcut("Ctrl+R")
+        action_refresh.triggered.connect(self._shortcut_refresh)
+        view_menu.addAction(action_refresh)
+
         # Help menu
         help_menu = menubar.addMenu("&Help")
 

src/cmdforge/gui/styles.py

@@ -1,6 +1,9 @@
-"""Modern stylesheet for CmdForge GUI."""
+"""Theme stylesheets for CmdForge GUI."""
 
-STYLESHEET = """
+from pathlib import Path
+
+# Light theme (default)
+LIGHT_THEME = """
 /* Main Window */
 QMainWindow {
     background-color: #f5f5f5;
@@ -401,4 +404,534 @@ QRadioButton::indicator:checked {
     border-radius: 9px;
     background-color: #667eea;
 }
+
+/* Menu bar */
+QMenuBar {
+    background-color: #f7fafc;
+    border-bottom: 1px solid #e2e8f0;
+}
+
+QMenuBar::item {
+    padding: 6px 12px;
+    background-color: transparent;
+}
+
+QMenuBar::item:selected {
+    background-color: #e2e8f0;
+}
+
+QMenu {
+    background-color: white;
+    border: 1px solid #e2e8f0;
+}
+
+QMenu::item {
+    padding: 8px 24px;
+}
+
+QMenu::item:selected {
+    background-color: #667eea;
+    color: white;
+}
+
+QMenu::separator {
+    height: 1px;
+    background-color: #e2e8f0;
+    margin: 4px 8px;
+}
 """
+
+# Dark theme
+DARK_THEME = """
+/* Main Window */
+QMainWindow {
+    background-color: #1a1a2e;
+}
+
+/* Sidebar */
+#sidebar {
+    background-color: #16213e;
+    border: none;
+    min-width: 180px;
+    max-width: 180px;
+}
+
+#sidebar::item {
+    color: #a0aec0;
+    padding: 12px 16px;
+    border: none;
+    border-left: 3px solid transparent;
+}
+
+#sidebar::item:selected {
+    background-color: #1f3460;
+    border-left: 3px solid #667eea;
+    color: white;
+}
+
+#sidebar::item:hover:!selected {
+    background-color: #1a2d50;
+}
+
+/* Content area */
+QWidget#content_area {
+    background-color: #1a1a2e;
+}
+
+/* Buttons */
+QPushButton {
+    background-color: #667eea;
+    color: white;
+    border: none;
+    border-radius: 6px;
+    padding: 8px 16px;
+    font-weight: 500;
+    min-height: 32px;
+}
+
+QPushButton:hover {
+    background-color: #7c8ff0;
+}
+
+QPushButton:pressed {
+    background-color: #5a67d8;
+}
+
+QPushButton:disabled {
+    background-color: #4a5568;
+    color: #718096;
+}
+
+QPushButton#secondary {
+    background-color: #2d3748;
+    color: #e2e8f0;
+}
+
+QPushButton#secondary:hover {
+    background-color: #4a5568;
+}
+
+QPushButton#danger {
+    background-color: #e53e3e;
+}
+
+QPushButton#danger:hover {
+    background-color: #fc5c65;
+}
+
+/* View toggle buttons */
+QPushButton#viewToggle {
+    background-color: #2d3748;
+    color: #a0aec0;
+    border-radius: 4px;
+    padding: 6px 12px;
+    min-height: 24px;
+    min-width: 60px;
+}
+
+QPushButton#viewToggle:checked {
+    background-color: #667eea;
+    color: white;
+}
+
+QPushButton#viewToggle:hover:!checked {
+    background-color: #4a5568;
+}
+
+/* Input fields */
+QLineEdit, QTextEdit, QPlainTextEdit {
+    border: 1px solid #4a5568;
+    border-radius: 6px;
+    padding: 8px 12px;
+    background-color: #2d3748;
+    color: #e2e8f0;
+    selection-background-color: #667eea;
+}
+
+QLineEdit:focus, QTextEdit:focus, QPlainTextEdit:focus {
+    border-color: #667eea;
+    outline: none;
+}
+
+/* Combo boxes */
+QComboBox {
+    border: 1px solid #4a5568;
+    border-radius: 6px;
+    padding: 8px 12px;
+    background-color: #2d3748;
+    color: #e2e8f0;
+    min-height: 20px;
+}
+
+QComboBox:focus {
+    border-color: #667eea;
+}
+
+QComboBox::drop-down {
+    border: none;
+    width: 24px;
+}
+
+QComboBox::down-arrow {
+    image: none;
+    border-left: 5px solid transparent;
+    border-right: 5px solid transparent;
+    border-top: 6px solid #a0aec0;
+    margin-right: 8px;
+}
+
+QComboBox QAbstractItemView {
+    border: 1px solid #4a5568;
+    background-color: #2d3748;
+    color: #e2e8f0;
+    selection-background-color: #667eea;
+}
+
+/* Lists and Trees */
+QListWidget, QTreeWidget, QTableWidget {
+    border: 1px solid #4a5568;
+    border-radius: 6px;
+    background-color: #2d3748;
+    color: #e2e8f0;
+    outline: none;
+}
+
+QListWidget::item, QTreeWidget::item {
+    padding: 8px 12px;
+    border: none;
+}
+
+QListWidget::item:selected, QTreeWidget::item:selected {
+    background-color: #667eea;
+    color: white;
+}
+
+QListWidget::item:hover:!selected, QTreeWidget::item:hover:!selected {
+    background-color: #4a5568;
+}
+
+/* Table Widget */
+QTableWidget {
+    gridline-color: #4a5568;
+}
+
+QTableWidget::item {
+    padding: 8px;
+}
+
+QTableWidget::item:selected {
+    background-color: #667eea;
+    color: white;
+}
+
+QHeaderView::section {
+    background-color: #1a1a2e;
+    padding: 8px 12px;
+    border: none;
+    border-bottom: 1px solid #4a5568;
+    font-weight: 600;
+    color: #a0aec0;
+}
+
+/* Group boxes */
+QGroupBox {
+    font-weight: 600;
+    border: 1px solid #4a5568;
+    border-radius: 8px;
+    margin-top: 12px;
+    padding-top: 12px;
+    background-color: #2d3748;
+    color: #e2e8f0;
+}
+
+QGroupBox::title {
+    subcontrol-origin: margin;
+    subcontrol-position: top left;
+    left: 12px;
+    padding: 0 8px;
+    color: #e2e8f0;
+}
+
+/* Labels */
+QLabel {
+    color: #e2e8f0;
+}
+
+QLabel#heading {
+    font-size: 18px;
+    font-weight: 600;
+    color: #ffffff;
+}
+
+QLabel#subheading {
+    font-size: 14px;
+    color: #a0aec0;
+}
+
+QLabel#label {
+    font-weight: 500;
+    color: #cbd5e0;
+}
+
+QLabel#sectionHeading {
+    font-weight: 600;
+    font-size: 13px;
+    color: #e2e8f0;
+}
+
+/* Scrollbars */
+QScrollBar:vertical {
+    background-color: #1a1a2e;
+    width: 12px;
+    border-radius: 6px;
+}
+
+QScrollBar::handle:vertical {
+    background-color: #4a5568;
+    border-radius: 6px;
+    min-height: 30px;
+}
+
+QScrollBar::handle:vertical:hover {
+    background-color: #718096;
+}
+
+QScrollBar::add-line:vertical, QScrollBar::sub-line:vertical {
+    height: 0;
+}
+
+QScrollBar:horizontal {
+    background-color: #1a1a2e;
+    height: 12px;
+    border-radius: 6px;
+}
+
+QScrollBar::handle:horizontal {
+    background-color: #4a5568;
+    border-radius: 6px;
+    min-width: 30px;
+}
+
+QScrollBar::handle:horizontal:hover {
+    background-color: #718096;
+}
+
+QScrollBar::add-line:horizontal, QScrollBar::sub-line:horizontal {
+    width: 0;
+}
+
+/* Status bar */
+QStatusBar {
+    background-color: #16213e;
+    border-top: 1px solid #4a5568;
+    color: #a0aec0;
+}
+
+/* Splitter */
+QSplitter::handle {
+    background-color: #4a5568;
+}
+
+QSplitter::handle:horizontal {
+    width: 2px;
+}
+
+QSplitter::handle:vertical {
+    height: 2px;
+}
+
+/* Tabs */
+QTabWidget::pane {
+    border: 1px solid #4a5568;
+    border-radius: 6px;
+    background-color: #2d3748;
+}
+
+QTabBar::tab {
+    background-color: #1a1a2e;
+    border: 1px solid #4a5568;
+    border-bottom: none;
+    padding: 8px 16px;
+    margin-right: 2px;
+    border-top-left-radius: 6px;
+    border-top-right-radius: 6px;
+    color: #a0aec0;
+}
+
+QTabBar::tab:selected {
+    background-color: #2d3748;
+    border-bottom: 1px solid #2d3748;
+    color: #e2e8f0;
+}
+
+QTabBar::tab:hover:!selected {
+    background-color: #16213e;
+}
+
+/* Dialogs */
+QDialog {
+    background-color: #1a1a2e;
+}
+
+/* Message boxes */
+QMessageBox {
+    background-color: #1a1a2e;
+}
+
+QMessageBox QPushButton {
+    min-width: 80px;
+}
+
+/* Tool tips */
+QToolTip {
+    background-color: #4a5568;
+    color: white;
+    border: none;
+    padding: 6px 10px;
+    border-radius: 4px;
+}
+
+/* Progress bar */
+QProgressBar {
+    border: 1px solid #4a5568;
+    border-radius: 6px;
+    background-color: #2d3748;
+    text-align: center;
+    height: 20px;
+    color: #e2e8f0;
+}
+
+QProgressBar::chunk {
+    background-color: #667eea;
+    border-radius: 5px;
+}
+
+/* Spin boxes */
+QSpinBox, QDoubleSpinBox {
+    border: 1px solid #4a5568;
+    border-radius: 6px;
+    padding: 8px 12px;
+    background-color: #2d3748;
+    color: #e2e8f0;
+}
+
+QSpinBox:focus, QDoubleSpinBox:focus {
+    border-color: #667eea;
+}
+
+/* Check boxes and radio buttons */
+QCheckBox, QRadioButton {
+    spacing: 8px;
+    color: #e2e8f0;
+}
+
+QCheckBox::indicator, QRadioButton::indicator {
+    width: 18px;
+    height: 18px;
+}
+
+QCheckBox::indicator:unchecked {
+    border: 2px solid #4a5568;
+    border-radius: 4px;
+    background-color: #2d3748;
+}
+
+QCheckBox::indicator:checked {
+    border: 2px solid #667eea;
+    border-radius: 4px;
+    background-color: #667eea;
+}
+
+QRadioButton::indicator:unchecked {
+    border: 2px solid #4a5568;
+    border-radius: 9px;
+    background-color: #2d3748;
+}
+
+QRadioButton::indicator:checked {
+    border: 2px solid #667eea;
+    border-radius: 9px;
+    background-color: #667eea;
+}
+
+/* Menu bar */
+QMenuBar {
+    background-color: #16213e;
+    border-bottom: 1px solid #4a5568;
+    color: #e2e8f0;
+}
+
+QMenuBar::item {
+    padding: 6px 12px;
+    background-color: transparent;
+}
+
+QMenuBar::item:selected {
+    background-color: #1f3460;
+}
+
+QMenu {
+    background-color: #2d3748;
+    border: 1px solid #4a5568;
+    color: #e2e8f0;
+}
+
+QMenu::item {
+    padding: 8px 24px;
+}
+
+QMenu::item:selected {
+    background-color: #667eea;
+    color: white;
+}
+
+QMenu::separator {
+    height: 1px;
+    background-color: #4a5568;
+    margin: 4px 8px;
+}
+"""
+
+# Available themes
+THEMES = {
+    "light": LIGHT_THEME,
+    "dark": DARK_THEME,
+}
+
+# For backwards compatibility
+STYLESHEET = LIGHT_THEME
+
+
+def get_custom_theme_path() -> Path:
+    """Get path to custom theme file."""
+    return Path.home() / ".cmdforge" / "theme.qss"
+
+
+def load_theme(theme_name: str = "light") -> str:
+    """
+    Load a theme stylesheet.
+
+    Args:
+        theme_name: Name of theme ("light", "dark") or "custom" for external file
+
+    Returns:
+        The stylesheet string
+    """
+    # Check for custom theme file first
+    custom_path = get_custom_theme_path()
+    if theme_name == "custom" and custom_path.exists():
+        try:
+            return custom_path.read_text()
+        except Exception:
+            pass  # Fall back to light theme
+
+    # Return built-in theme
+    return THEMES.get(theme_name, LIGHT_THEME)
+
+
+def get_available_themes() -> list:
+    """Get list of available theme names."""
+    themes = list(THEMES.keys())
+    if get_custom_theme_path().exists():
+        themes.append("custom")
+    return themes