Built a SwiftUI flashcard app with persistent storage, animated card flipping, and swipe-based navigation. Users can add and delete custom cards, flip between question and answer states with a 3D rotation effect, and keep their deck saved locally using JSON encoding with UserDefaults.

• 3D card-flip animation for showing question and answer views
• Swipe left and right navigation with spring-based transitions
• Add-card sheet with validation for creating custom flashcards
• Delete flow plus local persistence using Codable + UserDefaults
• Starter deck seeding when the app is opened for the first time