🌙 Dark Theme Implementation for Codelf

This PR implements a comprehensive VS Code-inspired dark theme system for the Codelf project, addressing the need for modern dark mode support with automatic system theme detection and seamless user experience.

✨ Key Features

🎨 VS Code-Inspired Design

• Authentic Colors: Uses VS Code's actual dark theme color palette
• Professional Look: Maintains consistency with popular development environments
• High Contrast: Ensures excellent readability and accessibility

🔧 Complete Theme System

• Auto Detection: Automatically detects and follows system theme preference using prefers-color-scheme
• Manual Override: Users can manually switch between Light, Dark, and Auto modes
• Persistence: Theme preference is saved in localStorage and persists across sessions
• Smooth Transitions: All theme changes include elegant CSS transitions

🎯 User Experience

• Theme Toggle: Accessible dropdown in the top-right corner with three options:
  • ☀️ Light: Clean, bright interface (default)
  • 🌙 Dark: VS Code-inspired dark interface
  • ⚪ Auto: Follows system preference automatically
• Real-time Updates: Responds to OS theme changes when in Auto mode
• No Flash: Smooth theme application without layout disruption

🛠️ Technical Implementation

React Theme Management

// New theme hook for easy integration
const { isDark, toggleTheme, setTheme } = useTheme();

// Theme provider wraps the entire app
<ThemeProvider>
  <App />
</ThemeProvider>

CSS Variables System

// Maintainable theming with CSS custom properties
:root {
  --bg-primary: #ffffff;     /* Light theme */
  --text-primary: #373a3c;
}

body.dark {
  --bg-primary: #1e1e1e;     /* Dark theme */
  --text-primary: #cccccc;
}

VS Code Color Palette

• Backgrounds: #1e1e1e (editor), #252526 (sidebar), #3c3c3c (inputs)
• Text: #cccccc (primary), #969696 (muted), #ffffff (active)
• Accents: #007acc (links), #0e639c (focus), #264f78 (selection)
• Syntax: Authentic VS Code syntax highlighting colors

📁 Files Added/Modified

New Files

• src/hooks/useTheme.js - React theme management hook
• src/components/ThemeToggle.js - Theme toggle dropdown component
• styles/_theme-variables.scss - CSS custom properties for theming
• styles/_semantic-ui-overrides.scss - Dark theme overrides for UI components
• docs/DARK_THEME.md - Comprehensive documentation

Enhanced Files

• All SCSS files updated to use CSS variables
• Code syntax highlighting enhanced with VS Code colors
• Semantic UI components styled for dark theme compatibility
• Improved accessibility with ARIA labels and keyboard navigation

🧪 Browser Support

• Modern browsers with CSS custom properties support
• prefers-color-scheme media query support
• Graceful fallbacks for older browsers
• localStorage with error handling

📖 Usage Examples

For Users

1. Click the theme toggle (☀️/🌙/⚪) in the top-right corner
2. Select your preferred theme mode
3. Enjoy automatic system theme detection in Auto mode

For Developers

// Use theme variables in components
.my-component {
  background: var(--bg-primary);
  color: var(--text-primary);
  border: 1px solid var(--border-primary);
}

// Access theme state in React components
import { useTheme } from '../hooks/useTheme';

function MyComponent() {
  const { isDark, toggleTheme } = useTheme();
  return <button onClick={toggleTheme}>Toggle Theme</button>;
}

🎯 Component Coverage

• ✅ Main search interface and results
• ✅ Navigation bar and controls
• ✅ Code syntax highlighting
• ✅ Modal dialogs and dropdowns
• ✅ Form inputs and buttons
• ✅ All Semantic UI components
• ✅ Footer and notice sections

🔍 Testing

The implementation has been thoroughly tested for:

• Theme switching functionality
• System theme detection
• Persistence across page reloads
• Component visual consistency
• Accessibility compliance
• Performance optimization

📚 Documentation

Complete documentation is available in docs/DARK_THEME.md including:

• Usage instructions
• Developer guide
• Extension examples
• Color reference
• Migration notes

This implementation provides a modern, accessible, and comprehensive dark theme experience that enhances usability while maintaining the professional look and feel that developers expect from their tools.

Statistics: 18 files modified, 792 lines added, comprehensive theme system ready for production use.

💡 You can make Copilot smarter by setting up custom instructions, customizing its development environment and configuring Model Context Protocol (MCP) servers. Learn more Copilot coding agent tips in the docs.