- Add useDarkMode hook for managing theme state and persistence
- Integrate dark mode toggle button in app header
- Update all components with dark variant styles using Tailwind v4
- Create centralized style utilities for consistent theming
- Support system color scheme preference as fallback
- Store user preference in localStorage for persistence
- Replace all CSS custom properties with Tailwind utility classes
- Add tailwind.config.js with custom color palette matching Linear design
- Reduce index.css from 89 to 37 lines (58% reduction)
- Maintain consistent visual appearance with semantic color usage
- Update all components to use Tailwind classes instead of CSS variables