Add a theme switcher in the navigation bar that allows users to toggle between light and dark modes. The preference should be saved to localStorage and persist across sessions. Ensure all components respect the theme setting and transitions are smooth.

Build a flexible Card component with variants: default, bordered, elevated, and outline. Should support header, content, and footer slots. TypeScript props required. Include Storybook documentation with all variants and usage examples.

Users report the app getting slower after 10+ minutes of use. Found infinite re-renders in the NotificationBell component due to missing dependency array. Need to refactor the useEffect and add proper cleanup. React DevTools Profiler shows component rendering 1000+ times.

Add keyboard shortcuts: Cmd/Ctrl+K for search, Cmd/Ctrl+N for new item, Esc to close modals, arrow keys for navigation. Display shortcut hints on hover. Create ShortcutsHelp modal (trigger with ?). Must work on Mac and Windows.

The contact form shows validation errors immediately on page load instead of waiting for user input. Need to implement 'touched' state tracking so errors only appear after the user has interacted with a field. Currently using React Hook Form.