@import url('https://fonts.googleapis.com/css2?family=Pretendard:wght@400;500;600;700;800&display=swap');

:root {
    /* Toss-inspired Color Palette with Christmas Theme */
    --primary-red: #ff3030;
    --primary-green: #0E6245;
    --primary-gold: #FFB800;
    --bg-primary: #FFFFFF;
    --bg-secondary: #F9FAFB;
    --bg-tertiary: #F3F4F6;
    --text-primary: #191F28;
    --text-secondary: #6B7684;
    --text-tertiary: #A0A8B4;
    --divider: #E5E8EB;
    --christmas-accent: #E31C1C;

    /* Gradients - More Subtle */
    --gradient-primary: linear-gradient(135deg, #FF3B30 0%, #E31C1C 100%);
    --gradient-secondary: linear-gradient(135deg, #0E6245 0%, #084030 100%);
    --gradient-gold: linear-gradient(135deg, #FFB800 0%, #FF8A00 100%);
    --gradient-bg: linear-gradient(180deg, #0E6245 0%, #1a5c42 100%);

    /* Shadows - Enhanced 3D depth shadows */
    --shadow-xs: 0 1px 3px 0 rgba(0, 0, 0, 0.06);
    --shadow-sm: 0 3px 6px -1px rgba(0, 0, 0, 0.1), 0 2px 4px -1px rgba(0, 0, 0, 0.06);
    --shadow-md: 0 10px 15px -3px rgba(0, 0, 0, 0.15), 0 4px 6px -2px rgba(0, 0, 0, 0.08);
    --shadow-lg: 0 20px 25px -5px rgba(0, 0, 0, 0.2), 0 10px 10px -5px rgba(0, 0, 0, 0.08);
    --shadow-xl: 0 25px 50px -12px rgba(0, 0, 0, 0.25), 0 12px 20px -8px rgba(0, 0, 0, 0.12);
    --shadow-btn: 0 4px 12px 0 rgba(0, 0, 0, 0.12), 0 2px 6px 0 rgba(0, 0, 0, 0.08);
    --shadow-3d: 0 30px 60px -15px rgba(0, 0, 0, 0.3), 0 15px 30px -10px rgba(0, 0, 0, 0.15);

    /* Spacing - Toss uses generous spacing */
    --spacing-xs: 4px;
    --spacing-sm: 8px;
    --spacing-md: 16px;
    --spacing-lg: 24px;
    --spacing-xl: 32px;
    --spacing-2xl: 48px;

    /* Border Radius - Larger for modern feel */
    --radius-sm: 8px;
    --radius-md: 12px;
    --radius-lg: 16px;
    --radius-xl: 20px;
    --radius-2xl: 24px;

    /* Typography */
    --font-family: 'Pretendard', -apple-system, BlinkMacSystemFont, system-ui, sans-serif;
    --font-size-xs: 11px;
    --font-size-sm: 13px;
    --font-size-md: 15px;
    --font-size-lg: 17px;
    --font-size-xl: 20px;
    --font-size-2xl: 26px;
    --font-size-3xl: 32px;
}

* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

body {
    font-family: var(--font-family);
    background: var(--gradient-bg);
    color: var(--text-primary);
    overflow-x: hidden;
    min-height: 100vh;
    position: relative;
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
    perspective: 1500px;
}

/* Snowfall Animation */
.snowflakes {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    pointer-events: none;
    z-index: 9999;
    overflow: hidden;
}

.snowflake {
    position: absolute;
    top: -10px;
    color: rgba(255, 255, 255, 0.7);
    font-size: 1em;
    animation: fall linear infinite;
    opacity: 0.6;
    text-shadow: 0 0 3px rgba(255, 255, 255, 0.3);
}

@keyframes fall {
    to {
        transform: translateY(100vh);
    }
}

/* Container - Toss-style generous padding */
.container {
    max-width: 480px;
    margin: 0 auto;
    padding: var(--spacing-lg) var(--spacing-md);
    min-height: 100vh;
    position: relative;
    z-index: 1;
}

/* Header - Clean and minimal */
.header {
    text-align: center;
    padding: var(--spacing-2xl) 0 var(--spacing-xl);
    animation: fadeInDown 0.6s ease-out;
}

.header h1 {
    font-size: var(--font-size-3xl);
    font-weight: 800;
    color: #FFFFFF;
    margin-bottom: var(--spacing-sm);
    letter-spacing: -0.02em;
    line-height: 1.2;
}

.header-decoration {
    font-size: var(--font-size-2xl);
    margin: 0 var(--spacing-xs);
}

.header p {
    font-size: var(--font-size-md);
    color: rgba(255, 255, 255, 0.85);
    font-weight: 500;
    letter-spacing: -0.01em;
}

/* Search Box - 3D Card Effect */
.search-box {
    background: var(--bg-primary);
    border-radius: var(--radius-2xl);
    padding: var(--spacing-lg);
    margin-bottom: var(--spacing-xl);
    box-shadow: var(--shadow-lg);
    animation: fadeIn 0.6s ease-out 0.2s both;
    border: 1px solid rgba(255, 255, 255, 0.8);
    transform: translateZ(20px);
    transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
    position: relative;
}

.search-box:hover {
    transform: translateZ(40px) translateY(-4px);
    box-shadow: var(--shadow-3d);
}

.search-input {
    width: 100%;
    padding: var(--spacing-md) var(--spacing-lg);
    font-size: var(--font-size-lg);
    border: none;
    border-radius: var(--radius-lg);
    font-family: var(--font-family);
    transition: all 0.2s ease;
    background: var(--bg-secondary);
    color: var(--text-primary);
    font-weight: 600;
    letter-spacing: -0.01em;
}

.search-input:focus {
    outline: none;
    background: var(--bg-tertiary);
    transform: translateZ(10px);
}

.search-input::placeholder {
    color: var(--text-tertiary);
    font-weight: 500;
}

/* Keywords Section - Toss-style */
.keywords-section {
    margin-bottom: var(--spacing-xl);
    animation: fadeIn 0.6s ease-out 0.4s both;
}

.keywords-section h2 {
    font-size: var(--font-size-xl);
    margin-bottom: var(--spacing-lg);
    color: #FFFFFF;
    font-weight: 700;
    letter-spacing: -0.02em;
}

.keywords-grid {
    display: flex;
    flex-wrap: wrap;
    gap: var(--spacing-sm);
}

.keyword-btn {
    padding: var(--spacing-md) var(--spacing-lg);
    border: none;
    background: rgba(255, 255, 255, 0.15);
    color: #FFFFFF;
    border-radius: var(--radius-2xl);
    font-size: var(--font-size-md);
    font-family: var(--font-family);
    cursor: pointer;
    transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
    backdrop-filter: blur(10px);
    font-weight: 600;
    letter-spacing: -0.01em;
    border: 1.5px solid rgba(255, 255, 255, 0.2);
    transform: translateZ(10px);
    box-shadow: var(--shadow-sm);
    position: relative;
}

.keyword-btn:hover {
    background: rgba(255, 255, 255, 0.25);
    border-color: rgba(255, 255, 255, 0.4);
    transform: translateZ(25px) translateY(-3px) scale(1.02);
    box-shadow: var(--shadow-lg);
}

.keyword-btn.active {
    background: #FFFFFF;
    color: var(--primary-green);
    border-color: #FFFFFF;
    box-shadow: var(--shadow-xl);
    transform: translateZ(30px) scale(1.05);
}

/* Primary Button - 3D Effect */
.btn-primary {
    width: 100%;
    padding: var(--spacing-lg) var(--spacing-xl);
    background: #FFFFFF;
    color: var(--primary-green);
    border: none;
    border-radius: var(--radius-xl);
    font-size: var(--font-size-xl);
    font-weight: 700;
    font-family: var(--font-family);
    cursor: pointer;
    transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
    box-shadow: var(--shadow-xl);
    animation: fadeIn 0.6s ease-out 0.6s both;
    letter-spacing: -0.02em;
    transform: translateZ(30px);
    position: relative;
}

.btn-primary:hover {
    transform: translateZ(50px) translateY(-6px);
    box-shadow: var(--shadow-3d);
}

.btn-primary:active {
    transform: translateZ(20px) translateY(-2px);
    box-shadow: var(--shadow-lg);
}

/* Kakao Login Button - 3D Style */
.kakao-login-btn {
    width: 100%;
    padding: var(--spacing-lg);
    background: #FEE500;
    color: #000000;
    border: none;
    border-radius: var(--radius-xl);
    font-size: var(--font-size-lg);
    font-weight: 700;
    font-family: var(--font-family);
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: center;
    gap: var(--spacing-sm);
    transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
    box-shadow: var(--shadow-lg);
    margin-top: var(--spacing-xl);
    letter-spacing: -0.01em;
    transform: translateZ(25px);
    position: relative;
}

.kakao-login-btn:hover {
    background: #FFD93D;
    transform: translateZ(45px) translateY(-4px);
    box-shadow: var(--shadow-3d);
}

.kakao-icon {
    width: 20px;
    height: 20px;
}

.save-btn {
  width: 100%;
  padding: var(--spacing-lg);
  background: rgba(176, 44, 44, 0.36);
  border: 2px solid rgba(220, 80, 80, 0.5);
  color: #fff2f2;
  border-radius: var(--radius-xl);
  font-size: var(--font-size-lg);
  font-weight: 700;
  font-family: var(--font-family);
  cursor: pointer;
  transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
  margin-top: var(--spacing-lg);
  letter-spacing: -0.01em;
  transform: translateZ(20px);
  box-shadow: var(--shadow-md);
  position: relative;
}

.save-btn:hover {
  background: rgba(176, 44, 44, 0.5);
  border-color: rgba(240, 120, 120, 0.7);
  transform: translateZ(35px) translateY(-3px);
  box-shadow: var(--shadow-lg);
}

/* Result Card - 3D Card with Depth */
.result-card {
    background: var(--bg-primary);
    border-radius: var(--radius-2xl);
    padding: var(--spacing-2xl) var(--spacing-xl);
    margin-bottom: var(--spacing-xl);
    box-shadow: var(--shadow-3d);
    animation: scaleIn 0.5s ease-out;
    color: var(--text-primary);
    border: 1px solid rgba(255, 255, 255, 0.8);
    transform: translateZ(40px);
    transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
    position: relative;
}

.result-card:hover {
    transform: translateZ(60px) translateY(-5px);
    box-shadow: 0 35px 70px -20px rgba(0, 0, 0, 0.35), 0 18px 35px -12px rgba(0, 0, 0, 0.18);
}

.book-image-container {
        text-align: center;
        margin-bottom: var(--spacing-xl);
 }

/* 이미지 래퍼: 이미지 크기에 딱 맞는 박스로 버튼이 겹치도록 함 */
.image-wrapper {
    display: inline-block;
    position: relative;
}

.book-image {
    max-width: 220px;
    height: auto;
    border-radius: var(--radius-lg);
    box-shadow: var(--shadow-xl);
    transition: transform 0.3s cubic-bezier(0.4, 0, 0.2, 1);
    transform: translateZ(20px);
    display: block; /* ensure wrapper matches image size */
    position: relative;
    z-index: 1; /* sit under the heart button */
}

.book-image:hover {
    transform: translateZ(40px) scale(1.05) rotateY(5deg);
    box-shadow: var(--shadow-3d);
}

/* Wishlist (찜) 버튼 - 책 이미지 오른쪽 하단 오버레이 */
.wishlist-btn {
    position: absolute;
    right: 12px;
    bottom: 12px;
    width: 44px;
    height: 44px;
    display: inline-flex;
    align-items: center;
    justify-content: center;
    background: transparent;
    border: none;
    cursor: pointer;
    border-radius: 50%;
    box-shadow: none;
    transition: transform 0.12s ease, box-shadow 0.12s ease;
    z-index: 40;
}

.wishlist-btn:focus {
    outline: none;
    transform: scale(1.08);
}

.heart-icon {
    width: 26px;
    height: 26px;
    display: block;
    fill: transparent;
    stroke: rgba(255, 255, 255, 0.95);
    stroke-width: 1.3;
    transition: fill 0.18s ease, stroke 0.18s ease, transform 0.12s ease;
    filter: drop-shadow(0 1px 2px rgba(0, 0, 0, 0.3));
}

/* 활성화된 상태: 내부 채우기 (붉은색) */
.wishlist-btn.active .heart-icon {
    fill: var(--primary-red);
    stroke: var(--primary-red);
    transform: scale(1.05);
    filter: drop-shadow(0 2px 6px rgba(0, 0, 0, 0.4));
}

/* 터치 피드백 */
.wishlist-btn:active {
    transform: scale(0.94);
    box-shadow: var(--shadow-md);
}

.title-wrapper {
    display: flex;
    align-items: center;
    gap: var(--spacing-sm);
    margin-bottom: var(--spacing-sm);
}

.book-info h2 {
    font-size: var(--font-size-2xl);
    color: var(--text-primary);
    margin-bottom: var(--spacing-sm);
    font-weight: 800;
    letter-spacing: -0.02em;
    line-height: 1.3;
}

.wishlist-btn-inline {
    width: 28px;
    height: 28px;
    display: inline-flex;
    align-items: center;
    justify-content: center;
    background: transparent;
    border: none;
    cursor: pointer;
    padding: 0;
    flex-shrink: 0;
    transition: transform 0.12s ease, opacity 0.12s ease;
}

.wishlist-btn-inline:focus {
    outline: none;
    transform: scale(1.1);
}

.heart-icon-inline {
    width: 24px;
    height: 24px;
    display: block;
    fill: transparent;
    stroke: var(--primary-red);
    stroke-width: 1.5;
    transition: fill 0.18s ease, stroke 0.18s ease, transform 0.12s ease, filter 0.12s ease;
}

.wishlist-btn-inline.active .heart-icon-inline {
    fill: var(--primary-red);
    stroke: var(--primary-red);
    transform: scale(1.05);
}

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

.book-info .author {
    font-size: var(--font-size-lg);
    color: var(--text-secondary);
    margin-bottom: var(--spacing-sm);
    font-weight: 600;
}

.book-info .publisher {
    font-size: var(--font-size-md);
    color: var(--text-tertiary);
    margin-bottom: var(--spacing-xl);
    font-weight: 500;
}

.recommendation-reason, .book-description {
    background: var(--bg-secondary);
    padding: var(--spacing-lg);
    border-radius: var(--radius-lg);
    margin-bottom: var(--spacing-xl);
    border: 1px solid rgba(14, 98, 69, 0.08);
    box-shadow: var(--shadow-md);
    transform: translateZ(10px);
    transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
}

.recommendation-reason:hover, .book-description:hover {
    transform: translateZ(20px);
    box-shadow: var(--shadow-lg);
}

.recommendation-reason, .book-description h3 {
    font-size: var(--font-size-xl);
    color: var(--text-primary);
    margin-bottom: var(--spacing-md);
    font-weight: 700;
    letter-spacing: -0.01em;
}

.recommendation-reason, .book-description p {
    font-size: var(--font-size-md);
    line-height: 1.7;
    color: var(--text-secondary);
    font-weight: 500;
    letter-spacing: -0.005em;
}

/* Back Button - 3D Style */
.back-btn {
    width: 100%;
    padding: var(--spacing-lg);
    background: transparent;
    color: #FFFFFF;
    border: 2px solid rgba(255, 255, 255, 0.3);
    border-radius: var(--radius-xl);
    font-size: var(--font-size-lg);
    font-weight: 700;
    font-family: var(--font-family);
    cursor: pointer;
    transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
    margin-top: var(--spacing-lg);
    letter-spacing: -0.01em;
    transform: translateZ(20px);
    box-shadow: var(--shadow-md);
    position: relative;
}

.back-btn:hover {
    background: rgba(255, 255, 255, 0.15);
    border-color: rgba(255, 255, 255, 0.5);
    transform: translateZ(35px) translateY(-3px);
    box-shadow: var(--shadow-lg);
}

/* Hidden Class */
.hidden {
    display: none !important;
}

/* Animations */
@keyframes fadeIn {
    from {
        opacity: 0;
        transform: translateY(20px);
    }

    to {
        opacity: 1;
        transform: translateY(0);
    }
}

@keyframes fadeInDown {
    from {
        opacity: 0;
        transform: translateY(-20px);
    }

    to {
        opacity: 1;
        transform: translateY(0);
    }
}

@keyframes scaleIn {
    from {
        opacity: 0;
        transform: scale(0.9);
    }

    to {
        opacity: 1;
        transform: scale(1);
    }
}

/* Loading Spinner */
.loading {
    display: inline-block;
    width: 20px;
    height: 20px;
    border: 3px solid rgba(255, 255, 255, 0.3);
    border-radius: 50%;
    border-top-color: var(--christmas-white);
    animation: spin 0.8s linear infinite;
}

@keyframes spin {
    to {
        transform: rotate(360deg);
    }
}

/* Mobile Optimization */
@media (max-width: 480px) {
    .container {
        padding: var(--spacing-md);
    }

    .header h1 {
        font-size: var(--font-size-xl);
    }

    .header-decoration {
        font-size: var(--font-size-md);
    }
}

/* Touch Feedback */
.keyword-btn:active,
.btn-primary:active,
.kakao-login-btn:active,
.back-btn:active {
    transform: scale(0.98);
}


/* Slider Section */
.slider-section {
  margin-top: var(--spacing-xl);
  transform: translateZ(30px);
}

.slider-title {
  font-size: var(--font-size-lg);
  font-weight: 700;
  color: #ffffff;
  margin-bottom: var(--spacing-md);
  letter-spacing: -0.01em;
}

/* Horizontal Slider (리디/밀리 스타일 핵심) */
.book-slider {
  display: flex;
  gap: var(--spacing-md);

  overflow-x: auto;
  scroll-snap-type: x mandatory;

  padding: 0 var(--spacing-md) var(--spacing-lg); /* ✅ 좌우 여백 추가 */
  margin: 0 calc(-1 * var(--spacing-md));         /* ✅ 컨테이너 밖까지 스치게 */

  -webkit-overflow-scrolling: touch;
}

.book-slider::-webkit-scrollbar {
  display: none;
}

/* Slider Card */
.slider-card {
  flex: 0 0 150px;                 /* ✅ 살짝 줄여서 다음 카드 노출 */
  background: var(--bg-primary);
  border-radius: var(--radius-xl);
  overflow: hidden;

  scroll-snap-align: start;
  box-shadow: var(--shadow-lg);

  transition: transform 0.25s ease, box-shadow 0.25s ease;
}

/* 모바일 기준: hover 대신 액티브 느낌 */
.slider-card:active {
  transform: scale(0.97);
}

/* Cover */
.slider-card img {
  width: 100%;
  height: 210px;
  object-fit: cover;
  background: #f3f4f6;
}

/* Info */
.slider-card .info {
  padding: var(--spacing-sm) var(--spacing-md);
}

.slider-card .title {
  font-size: var(--font-size-sm);
  font-weight: 700;
  color: var(--text-primary);
  line-height: 1.3;

  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
}

.slider-card .author {
  margin-top: 2px;
  font-size: var(--font-size-xs);
  color: var(--text-secondary);
}

.description-wrapper {
  overflow: hidden;
  transition: max-height 0.35s ease;
}

.description-wrapper.collapsed {
  max-height: 4.5em; /* 3줄 정도 */
}

.description-wrapper.expanded {
  max-height: 1000px;
}

.more-btn {
  margin-top: 8px;
  background: none;
  border: none;
  color: #165B33;
  font-size: 0.9rem;
  font-weight: 600;
  cursor: pointer;
}

.more-btn:hover {
  text-decoration: underline;
}