/* 카드 스와이퍼 커스텀 스타일 */
.card-swiper {
    width: 100%;
    height: calc(100vh - 180px);
    padding: 20px 0;
}

.card-swiper .swiper-slide {
    display: flex;
    justify-content: center;
    align-items: center;
    perspective: 1000px;
}

/* 카드 스타일 */
.card {
    width: 100%;
    max-width: 500px;
    height: 100%;
    position: relative;
    transform-style: preserve-3d;
    transition: transform 0.6s;
    cursor: pointer;
}

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

.card-front,
.card-back {
    position: absolute;
    width: 100%;
    height: 100%;
    backface-visibility: hidden;
    border-radius: 16px;
    box-shadow: 0 10px 30px rgba(0, 0, 0, 0.2);
    padding: 24px;
    overflow-y: auto;
}

.card-front {
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    color: white;
    display: flex;
    flex-direction: column;
}

.card-back {
    background: linear-gradient(135deg, #f093fb 0%, #f5576c 100%);
    color: white;
    transform: rotateY(180deg);
    display: flex;
    flex-direction: column;
}

/* 카드 내용 스타일 */
.card-question {
    font-size: 1.5rem;
    font-weight: bold;
    margin-bottom: 16px;
    line-height: 1.6;
}

.card-answer {
    font-size: 1.1rem;
    line-height: 1.8;
    margin-bottom: 24px;
}

.sub-question {
    background: rgba(255, 255, 255, 0.2);
    border-radius: 8px;
    padding: 12px;
    margin-bottom: 12px;
}

.sub-question-title {
    font-weight: bold;
    margin-bottom: 8px;
    font-size: 1rem;
}

.sub-question-answer {
    font-size: 0.9rem;
    line-height: 1.6;
}

/* 태그 스타일 */
.card-tags {
    display: flex;
    flex-wrap: wrap;
    gap: 8px;
    margin-bottom: 16px;
}

.tag {
    background: rgba(255, 255, 255, 0.3);
    padding: 4px 12px;
    border-radius: 12px;
    font-size: 0.875rem;
    font-weight: 500;
}

/* 난이도 배지 */
.difficulty-badge {
    display: inline-block;
    padding: 4px 12px;
    border-radius: 12px;
    font-size: 0.875rem;
    font-weight: 600;
    margin-bottom: 16px;
}

.difficulty-EASY {
    background: rgba(34, 197, 94, 0.3);
}

.difficulty-MEDIUM {
    background: rgba(251, 191, 36, 0.3);
}

.difficulty-HARD {
    background: rgba(239, 68, 68, 0.3);
}

/* 버튼 스타일 */
.verify-btn {
    margin-top: auto;
    padding: 12px 24px;
    background: rgba(255, 255, 255, 0.3);
    border: 2px solid white;
    border-radius: 8px;
    color: white;
    font-weight: 600;
    cursor: pointer;
    transition: all 0.3s;
}

.verify-btn:hover {
    background: rgba(255, 255, 255, 0.5);
}

.verify-btn:active {
    transform: scale(0.95);
}

/* 필터 버튼 활성화 */
.filter-active {
    background: #3b82f6 !important;
    color: white !important;
    border-color: #3b82f6 !important;
}

/* 모바일 반응형 */
@media (max-width: 640px) {
    .card-swiper {
        height: calc(100vh - 160px);
    }
    
    .card-question {
        font-size: 1.25rem;
    }
    
    .card-answer {
        font-size: 1rem;
    }
}

/* 태블릿 반응형 */
@media (min-width: 641px) and (max-width: 1024px) {
    .card-swiper {
        height: calc(100vh - 180px);
    }
}

/* PC 반응형 */
@media (min-width: 1025px) {
    .card-swiper {
        height: calc(100vh - 200px);
    }
    
    .card {
        max-width: 600px;
    }
}

/* 스크롤바 스타일 */
.card-front::-webkit-scrollbar,
.card-back::-webkit-scrollbar {
    width: 6px;
}

.card-front::-webkit-scrollbar-track,
.card-back::-webkit-scrollbar-track {
    background: rgba(255, 255, 255, 0.1);
    border-radius: 10px;
}

.card-front::-webkit-scrollbar-thumb,
.card-back::-webkit-scrollbar-thumb {
    background: rgba(255, 255, 255, 0.3);
    border-radius: 10px;
}

.card-front::-webkit-scrollbar-thumb:hover,
.card-back::-webkit-scrollbar-thumb:hover {
    background: rgba(255, 255, 255, 0.5);
}