A study deck with flip animation and progress tracking, built in ~10 minutes.
Build a flashcards study app in React with: - A deck of cards with front/question and back/answer - Click the card to flip it (CSS 3D transform with backface-visibility) - Mark Known / Needs Review buttons that advance to the next card - Shuffle button to randomize the order - Add new cards via a small form - Counter showing "card X of Y" and tallies for Known / Reviewing - Dark UI, no external dependencies