.puzzle-tile {
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    border-radius: 8px;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 32px;
    font-weight: 700;
    color: white;
    cursor: pointer;
    transition: all 0.2s ease;
    box-shadow: 0 4px 6px rgba(0, 0, 0, 0.3);
    user-select: none;
}

.puzzle-tile:hover:not(.empty) {
    transform: scale(1.05);
    box-shadow: 0 6px 12px rgba(0, 0, 0, 0.4);
}

.puzzle-tile.empty {
    background: rgba(255, 255, 255, 0.05);
    cursor: default;
    box-shadow: none;
}

.puzzle-tile:active:not(.empty) {
    transform: scale(0.95);
}