Calm Quartz Whirl Gnu

Flashcard system with spaced repetition and mastery tracking.

- Flashcard creation with stimulus and response pairs
- Multi-level mastery system using review intervals
- Spaced repetition scheduling for card reviews
- Customizable decks with individual color and icon selection
- Interactive session interface with haptic feedback
- Performance reporting after each review session
- Persistent local storage for user decks and study progress
- Progress tracking with percentage and leveled mastery count
- Swipe-to-delete cards from existing decks
- Long-press to remove entire card collections