I'll make the chat responsive and add the requested features: user profiles and dark/light mode functionality.

I've updated the chat application to address all your requests:

1. Responsive Design

• The chat is now fully responsive and works well on mobile devices
• Added a mobile-specific header with a slide-out sidebar
• Implemented proper spacing and positioning for mobile views
• Fixed the message input to stay at the bottom of the screen on mobile

2. User Profiles

• Added profile viewing functionality for both contacts and the logged-in user
• Created a dialog that shows when clicking on a user's avatar
• For contacts: Shows their profile information including bio, email, phone, and location
• For the logged-in user: Added a tabbed interface with both view and edit modes

3. Light and Dark Mode

• Implemented theme toggle functionality using Next.js's ThemeProvider
• Added a moon/sun icon button to switch between light and dark modes
• Updated all UI components to respect the current theme
• Applied appropriate color schemes for both modes

Key Improvements:

• Mobile Navigation: Added a slide-out sidebar for mobile devices
• Responsive Layout: Adjusted layout and sizing for different screen sizes
• Profile Dialogs: Created modal dialogs for viewing user profiles
• Theme Toggle: Added theme switching with visual indicators
• User Experience: Improved overall UX with better navigation and accessibility

The application now provides a complete chat experience with responsive design, user profiles, and theme customization.

I'll fix the mobile navigation to use a back button instead of a hamburger menu, and fix the light/dark mode functionality.

I've made the requested changes to the chat application:

1. Mobile Navigation Improvements

• Removed the hamburger menu and slide-out sidebar

• Implemented a two-view approach for mobile:

  • Contacts View: Shows the list of all contacts
  • Chat View: Shows the active conversation
• Added a back button in the chat view that returns to the contacts list
• When a user clicks on a contact, it opens the chat view with that conversation

2. Fixed Light and Dark Mode

• Fixed the theme toggle functionality to properly apply theme changes
• Added immediate theme application using classList manipulation
• Ensured theme persistence using localStorage
• Made sure all components respect the current theme

How the Mobile Navigation Works Now:

1. On mobile, the app starts by showing the contacts list
2. When a user taps on a contact, it switches to the chat view with that conversation
3. The chat view has a back button (←) in the top left corner
4. Tapping the back button returns to the contacts list
5. This creates a more natural mobile navigation experience without slide-out menus

The desktop view remains unchanged with the side-by-side layout showing both contacts and the active conversation.