/* 기본 폰트 설정 및 모바일 터치 최적화 */
body {
    font-family: 'Noto Sans JP', sans-serif;
    -webkit-tap-highlight-color: transparent;
}

/* 플래시카드 뒤집기 3D 효과 */
.perspective-1000 {
    perspective: 1000px;
}

.card-inner {
    transition: transform 0.6s cubic-bezier(0.4, 0.2, 0.2, 1);
    transform-style: preserve-3d;
    position: relative;
    width: 100%;
    height: 100%;
}

.card.flipped .card-inner {
    transform: rotateY(180deg);
}

.card-front, .card-back {
    position: absolute;
    width: 100%;
    height: 100%;
    -webkit-backface-visibility: hidden;
    backface-visibility: hidden;
    border-radius: 0.75rem; /* rounded-xl */
}

.card-back {
    transform: rotateY(180deg);
}

/* 이미지 로딩 전 숨김 처리 */
.card-img {
    opacity: 0;
    transition: opacity 0.3s ease;
}

.card-img.loaded {
    opacity: 1;
}