Add Tailwind CSS styling

## Description
Implement proper styling using Tailwind CSS to improve the UI appearance.

## Requirements
- Set up Tailwind CSS properly with Trunk
- Create a consistent design system
- Style all components (buttons, cards, text)
- Add hover and active states
- Ensure responsive design

## Tasks
- [ ] Configure Tailwind with PostCSS
- [ ] Create base styles
- [ ] Style quiz card component
- [ ] Style buttons with proper states
- [ ] Add loading and transition animations
- [ ] Test on mobile devices