.flashcard-deck{display:flex;flex-wrap:wrap;gap:20px;justify-content:center}.flashcard{width:200px;height:140px;perspective:1000px}.flashcard .front,.flashcard .back{width:100%;height:100%;position:absolute;backface-visibility:hidden;border-radius:12px;display:flex;align-items:center;justify-content:center;font-size:1.3rem;font-weight:700;padding:10px;box-shadow:0 4px 12px rgba(0,0,0,.2);transition:transform .6s}.flashcard .front{background:#fff;color:#2d2d2d}.flashcard .back{background:#4a90e2;color:white;transform:rotateY(180deg)}.flashcard{position:relative;transform-style:preserve-3d;cursor:pointer}.flashcard:hover .front{transform:rotateY(180deg)}.flashcard:hover .back{transform:rotateY(360deg)}