/* ==========================================================================
   夜羽凌書籍展示與導購網站 - 設計系統與樣式
   ========================================================================== */

/* 引入 Google Fonts */
@import url('https://fonts.googleapis.com/css2?family=Inter:wght@300;400;500;600;700&family=Plus+Jakarta+Sans:wght@300;400;500;600;700;800&family=Noto+Sans+TC:wght@300;400;500;700&display=swap');

:root {
    /* 色彩系統 (暗色系主題，專業且具數位感) */
    --bg-dark: #0b0f19;
    --bg-card: #151c2c;
    --bg-card-hover: #1c263c;
    --bg-input: #101625;
    
    --primary: #6366f1; /* 靛藍色 Indigo */
    --primary-light: #818cf8;
    --primary-dark: #4f46e5;
    
    --accent: #f59e0b; /* 琥珀色 Amber */
    --accent-light: #fbbf24;
    
    --text-primary: #f3f4f6; /* 近白色 Gray 100 */
    --text-secondary: #9ca3af; /* 灰字 Gray 400 */
    --text-muted: #6b7280; /* 暗灰字 Gray 500 */
    
    --border-color: rgba(255, 255, 255, 0.08);
    --border-color-hover: rgba(255, 255, 255, 0.15);
    
    /* 漸層色 */
    --gradient-hero: linear-gradient(135deg, #0b0f19 0%, #111827 50%, #1e1b4b 100%);
    --gradient-primary: linear-gradient(135deg, #4f46e5 0%, #6366f1 100%);
    --gradient-accent: linear-gradient(135deg, #d97706 0%, #f59e0b 100%);
    --gradient-card: linear-gradient(180deg, rgba(21, 28, 44, 0.8) 0%, rgba(17, 24, 39, 0.9) 100%);
    --gradient-text: linear-gradient(135deg, #ffffff 0%, #cbd5e1 100%);
    --gradient-text-accent: linear-gradient(135deg, #818cf8 0%, #c084fc 100%);

    /* 字體與排版 */
    --font-sans: 'Plus Jakarta Sans', 'Inter', 'Noto Sans TC', -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif;
    
    /* 陰影與微光效果 */
    --shadow-sm: 0 1px 2px 0 rgba(0, 0, 0, 0.05);
    --shadow-md: 0 4px 6px -1px rgba(0, 0, 0, 0.1), 0 2px 4px -1px rgba(0, 0, 0, 0.06);
    --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.3), 0 4px 6px -2px rgba(0, 0, 0, 0.05);
    --shadow-glow: 0 0 20px rgba(99, 102, 241, 0.15);
    
    /* 圓角 */
    --radius-sm: 8px;
    --radius-md: 12px;
    --radius-lg: 20px;
    --radius-xl: 30px;
    
    /* 動態時間 */
    --transition-fast: 0.2s cubic-bezier(0.4, 0, 0.2, 1);
    --transition-normal: 0.3s cubic-bezier(0.4, 0, 0.2, 1);
    --transition-slow: 0.5s cubic-bezier(0.4, 0, 0.2, 1);
}

/* ==========================================================================
   基礎樣式與 Reset
   ========================================================================== */
* {
    box-sizing: border-box;
    margin: 0;
    padding: 0;
}

html {
    scroll-behavior: smooth;
    font-size: 16px;
}

body {
    background-color: var(--bg-dark);
    color: var(--text-primary);
    font-family: var(--font-sans);
    line-height: 1.7;
    -webkit-font-smoothing: antialiased;
    overflow-x: hidden;
}

img {
    max-width: 100%;
    height: auto;
    display: block;
}

a {
    color: inherit;
    text-decoration: none;
    transition: var(--transition-fast);
}

/* ==========================================================================
   通用版面元件與輔助類
   ========================================================================== */
.container {
    width: 100%;
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 24px;
}

.section {
    padding: 100px 0;
    position: relative;
}

.section-header {
    text-align: center;
    max-width: 700px;
    margin: 0 auto 60px auto;
}

.section-tag {
    display: inline-block;
    padding: 6px 16px;
    font-size: 0.85rem;
    font-weight: 600;
    color: var(--primary-light);
    background-color: rgba(99, 102, 241, 0.1);
    border: 1px solid rgba(99, 102, 241, 0.2);
    border-radius: var(--radius-xl);
    margin-bottom: 16px;
    letter-spacing: 1px;
    text-transform: uppercase;
}

.section-title {
    font-size: 2.25rem;
    font-weight: 700;
    line-height: 1.3;
    margin-bottom: 16px;
    background: var(--gradient-text);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
}

.section-desc {
    color: var(--text-secondary);
    font-size: 1.1rem;
}

/* 按鈕樣式 */
.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    padding: 12px 28px;
    font-size: 1rem;
    font-weight: 600;
    border-radius: var(--radius-md);
    cursor: pointer;
    transition: var(--transition-normal);
    border: none;
    outline: none;
    gap: 8px;
}

.btn-primary {
    background: var(--gradient-primary);
    color: #ffffff;
    box-shadow: var(--shadow-md), 0 4px 12px rgba(99, 102, 241, 0.3);
}

.btn-primary:hover {
    transform: translateY(-2px);
    box-shadow: var(--shadow-lg), 0 6px 20px rgba(99, 102, 241, 0.5);
    background: linear-gradient(135deg, #5a52e6 0%, #7578f8 100%);
}

.btn-secondary {
    background-color: rgba(255, 255, 255, 0.05);
    color: var(--text-primary);
    border: 1px solid var(--border-color);
}

.btn-secondary:hover {
    background-color: rgba(255, 255, 255, 0.1);
    border-color: var(--border-color-hover);
    transform: translateY(-2px);
}

.btn-accent {
    background: var(--gradient-accent);
    color: #ffffff;
    box-shadow: var(--shadow-md), 0 4px 12px rgba(245, 158, 11, 0.3);
}

.btn-accent:hover {
    transform: translateY(-2px);
    box-shadow: var(--shadow-lg), 0 6px 20px rgba(245, 158, 11, 0.5);
    background: linear-gradient(135deg, #c27803 0%, #fbbf24 100%);
}

.btn-sm {
    padding: 8px 18px;
    font-size: 0.9rem;
}

/* ==========================================================================
   Header & Navigation
   ========================================================================== */
header {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    z-index: 100;
    background-color: rgba(11, 15, 25, 0.7);
    backdrop-filter: blur(16px);
    -webkit-backdrop-filter: blur(16px);
    border-bottom: 1px solid var(--border-color);
    transition: var(--transition-normal);
}

header.scrolled {
    background-color: rgba(11, 15, 25, 0.9);
    border-bottom: 1px solid rgba(255, 255, 255, 0.08);
    box-shadow: var(--shadow-md);
}

.nav-wrapper {
    display: flex;
    justify-content: space-between;
    align-items: center;
    height: 80px;
    transition: var(--transition-normal);
}

header.scrolled .nav-wrapper {
    height: 64px;
}

.logo {
    font-size: 1.5rem;
    font-weight: 800;
    letter-spacing: -0.5px;
    background: var(--gradient-text-accent);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
}

.logo span {
    font-size: 0.85rem;
    font-weight: 500;
    color: var(--text-secondary);
    -webkit-text-fill-color: var(--text-secondary);
    margin-left: 8px;
    border-left: 1px solid var(--border-color);
    padding-left: 8px;
}

.nav-menu {
    display: flex;
    gap: 32px;
    list-style: none;
    align-items: center;
}

.nav-link {
    font-size: 0.95rem;
    font-weight: 500;
    color: var(--text-secondary);
}

.nav-link:hover, .nav-link.active {
    color: var(--text-primary);
}

/* 手機版選單切換按鈕 */
.nav-toggle {
    display: none;
    background: none;
    border: none;
    cursor: pointer;
    padding: 4px;
}

.nav-toggle span {
    display: block;
    width: 24px;
    height: 2px;
    background-color: var(--text-primary);
    margin: 5px 0;
    transition: var(--transition-fast);
}

/* ==========================================================================
   Hero 首頁主視覺區
   ========================================================================== */
.hero {
    min-height: 100vh;
    display: flex;
    align-items: center;
    padding-top: 120px;
    padding-bottom: 80px;
    background: var(--gradient-hero);
    position: relative;
    overflow: hidden;
}

/* 裝飾背景 */
.hero::before {
    content: '';
    position: absolute;
    top: -10%;
    right: -10%;
    width: 50%;
    height: 60%;
    background: radial-gradient(circle, rgba(99, 102, 241, 0.15) 0%, transparent 70%);
    z-index: 1;
    pointer-events: none;
}

.hero::after {
    content: '';
    position: absolute;
    bottom: -10%;
    left: -10%;
    width: 40%;
    height: 50%;
    background: radial-gradient(circle, rgba(192, 132, 252, 0.1) 0%, transparent 70%);
    z-index: 1;
    pointer-events: none;
}

.hero-grid {
    display: grid;
    grid-template-columns: 1.2fr 0.8fr;
    gap: 48px;
    align-items: center;
    position: relative;
    z-index: 2;
}

.hero-content {
    max-width: 680px;
}

.hero-badge {
    display: inline-flex;
    align-items: center;
    gap: 8px;
    padding: 6px 14px;
    background-color: rgba(255, 255, 255, 0.03);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-xl);
    font-size: 0.85rem;
    font-weight: 500;
    color: var(--text-secondary);
    margin-bottom: 24px;
}

.hero-badge-dot {
    width: 6px;
    height: 6px;
    background-color: var(--accent);
    border-radius: 50%;
    box-shadow: 0 0 8px var(--accent);
}

.hero-title {
    font-size: 3.5rem;
    font-weight: 800;
    line-height: 1.2;
    margin-bottom: 20px;
    letter-spacing: -1px;
}

.hero-title span {
    background: linear-gradient(135deg, #818cf8 0%, #cbd5e1 100%);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
}

.hero-desc {
    font-size: 1.2rem;
    color: var(--text-secondary);
    margin-bottom: 36px;
    line-height: 1.8;
}

.hero-actions {
    display: flex;
    gap: 16px;
    flex-wrap: wrap;
}

/* 右側書封展示卡疊 */
.hero-visual {
    display: flex;
    justify-content: center;
    align-items: center;
    position: relative;
    height: 420px;
}

.book-stack-placeholder {
    width: 260px;
    height: 360px;
    background: linear-gradient(135deg, #1f2937 0%, #111827 100%);
    border-radius: var(--radius-md);
    box-shadow: var(--shadow-lg);
    border: 1px solid var(--border-color);
    position: relative;
    transform: rotate(-4deg);
    transition: var(--transition-normal);
}

.book-stack-placeholder:hover {
    transform: rotate(0deg) scale(1.02);
}

.book-stack-img {
    width: 100%;
    height: 100%;
    object-fit: cover;
    border-radius: var(--radius-md);
}

.book-stack-back {
    position: absolute;
    width: 260px;
    height: 360px;
    border-radius: var(--radius-md);
    box-shadow: var(--shadow-md);
    border: 1px solid rgba(255, 255, 255, 0.05);
    z-index: -1;
    pointer-events: none;
}

.book-stack-back-1 {
    background: #151c2c;
    transform: translate(20px, 10px) rotate(4deg);
    opacity: 0.8;
}

.book-stack-back-2 {
    background: #0f131d;
    transform: translate(40px, 20px) rotate(10deg);
    opacity: 0.5;
}

/* ==========================================================================
   作者簡介區 (About Section)
   ========================================================================== */
.about {
    background-color: rgba(17, 24, 39, 0.5);
    border-top: 1px solid var(--border-color);
    border-bottom: 1px solid var(--border-color);
}

.about-grid {
    display: grid;
    grid-template-columns: 0.8fr 1.2fr;
    gap: 64px;
    align-items: center;
}

.about-avatar-wrapper {
    position: relative;
    display: flex;
    justify-content: center;
}

.about-avatar-wrapper::before {
    content: '';
    position: absolute;
    width: 240px;
    height: 240px;
    background: radial-gradient(circle, rgba(99, 102, 241, 0.15) 0%, transparent 70%);
    z-index: -1;
}

.about-avatar {
    width: 200px;
    height: 200px;
    border-radius: 50%;
    border: 3px solid var(--primary);
    padding: 6px;
    background-color: var(--bg-dark);
    box-shadow: var(--shadow-lg), var(--shadow-glow);
    display: flex;
    justify-content: center;
    align-items: center;
    overflow: hidden;
}

.about-avatar img {
    border-radius: 50%;
    width: 100%;
    height: 100%;
    object-fit: cover;
}

.about-avatar-placeholder {
    width: 100%;
    height: 100%;
    background: linear-gradient(135deg, #4f46e5 0%, #c084fc 100%);
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 3rem;
    font-weight: 700;
    color: white;
}

.about-info {
    max-width: 640px;
}

.about-name {
    font-size: 2rem;
    font-weight: 700;
    margin-bottom: 8px;
}

.about-title {
    font-size: 1rem;
    color: var(--primary-light);
    font-weight: 600;
    margin-bottom: 24px;
    letter-spacing: 1px;
}

.about-bio {
    color: var(--text-secondary);
    font-size: 1.05rem;
    margin-bottom: 32px;
}

.about-bio p {
    margin-bottom: 16px;
}

.about-stats {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 24px;
    border-top: 1px solid var(--border-color);
    padding-top: 32px;
}

.stat-item-title {
    font-size: 0.85rem;
    color: var(--text-muted);
    font-weight: 500;
    margin-bottom: 4px;
}

.stat-item-value {
    font-size: 1.5rem;
    font-weight: 700;
    color: var(--text-primary);
}

/* ==========================================================================
   書籍推薦區 (Books Section)
   ========================================================================== */
.books {
    background-color: var(--bg-dark);
}

/* 分類篩選器 */
.filter-wrapper {
    display: flex;
    justify-content: center;
    margin-bottom: 48px;
}

.filter-tabs {
    display: flex;
    background-color: rgba(255, 255, 255, 0.03);
    border: 1px solid var(--border-color);
    padding: 6px;
    border-radius: var(--radius-md);
    gap: 4px;
}

.filter-tab {
    background: none;
    border: none;
    outline: none;
    color: var(--text-secondary);
    font-size: 0.95rem;
    font-weight: 600;
    padding: 8px 20px;
    border-radius: var(--radius-sm);
    cursor: pointer;
    transition: var(--transition-fast);
}

.filter-tab:hover {
    color: var(--text-primary);
}

.filter-tab.active {
    background-color: var(--primary);
    color: #ffffff;
    box-shadow: var(--shadow-sm);
}

/* 書籍網格與商品卡片 */
.books-grid {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 32px;
}

.book-card {
    background: var(--gradient-card);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-lg);
    overflow: hidden;
    transition: var(--transition-normal);
    display: flex;
    flex-direction: column;
    height: 100%;
}

.book-card:hover {
    transform: translateY(-8px);
    border-color: var(--border-color-hover);
    box-shadow: var(--shadow-lg), var(--shadow-glow);
}

.book-card-image-wrap {
    padding: 32px 32px 0 32px;
    background-color: rgba(0, 0, 0, 0.15);
    display: flex;
    justify-content: center;
    position: relative;
    overflow: hidden;
}

.book-card-img-container {
    width: 100%;
    max-width: 180px;
    aspect-ratio: 3/4;
    border-radius: var(--radius-sm);
    box-shadow: 0 8px 24px rgba(0,0,0,0.4);
    overflow: hidden;
    transition: var(--transition-normal);
}

.book-card:hover .book-card-img-container {
    transform: scale(1.03);
    box-shadow: 0 12px 30px rgba(0,0,0,0.5);
}

.book-card-img {
    width: 100%;
    height: 100%;
    object-fit: cover;
}

.book-card-tag {
    position: absolute;
    top: 20px;
    right: 20px;
    padding: 4px 10px;
    font-size: 0.75rem;
    font-weight: 600;
    border-radius: var(--radius-sm);
    background-color: rgba(99, 102, 241, 0.2);
    border: 1px solid rgba(99, 102, 241, 0.3);
    color: var(--primary-light);
}

.book-card-body {
    padding: 28px;
    display: flex;
    flex-direction: column;
    flex-grow: 1;
}

.book-card-title {
    font-size: 1.35rem;
    font-weight: 700;
    margin-bottom: 12px;
    line-height: 1.4;
}

.book-card-desc {
    color: var(--text-secondary);
    font-size: 0.95rem;
    margin-bottom: 24px;
    flex-grow: 1;
}

.book-card-meta {
    border-top: 1px solid var(--border-color);
    padding-top: 20px;
    margin-top: auto;
}

.book-card-price-row {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 16px;
}

.book-card-price-label {
    font-size: 0.85rem;
    color: var(--text-muted);
}

.book-card-price {
    font-size: 1.25rem;
    font-weight: 700;
    color: var(--accent-light);
}

.book-card-price-disclaimer {
    font-size: 0.75rem;
    color: var(--text-muted);
    text-align: right;
    margin-top: 2px;
}

.book-card-actions {
    display: grid;
    grid-template-columns: 1fr;
    gap: 12px;
}

/* ==========================================================================
   書籍細節區 (Book Details Section)
   ========================================================================== */
.book-details {
    background-color: rgba(17, 24, 39, 0.3);
    border-top: 1px solid var(--border-color);
}

.detail-section-title {
    font-size: 1.75rem;
    font-weight: 700;
    margin-bottom: 40px;
    text-align: center;
    color: var(--text-primary);
    position: relative;
    display: inline-block;
    left: 50%;
    transform: translateX(-50%);
}

.detail-section-title::after {
    content: '';
    position: absolute;
    bottom: -8px;
    left: 10%;
    width: 80%;
    height: 3px;
    background: var(--gradient-primary);
    border-radius: 2px;
}

.book-detail-item {
    display: grid;
    grid-template-columns: 0.7fr 1.3fr;
    gap: 64px;
    margin-bottom: 100px;
    padding-bottom: 80px;
    border-bottom: 1px solid var(--border-color);
}

.book-detail-item:last-child {
    margin-bottom: 0;
    padding-bottom: 0;
    border-bottom: none;
}

.book-detail-left {
    display: flex;
    flex-direction: column;
    align-items: center;
}

.book-detail-cover {
    width: 240px;
    aspect-ratio: 3/4;
    border-radius: var(--radius-md);
    box-shadow: 0 12px 36px rgba(0,0,0,0.5);
    overflow: hidden;
    margin-bottom: 24px;
    border: 1px solid var(--border-color);
}

.book-detail-cover img {
    width: 100%;
    height: 100%;
    object-fit: cover;
}

.book-detail-spec {
    width: 100%;
    max-width: 240px;
    background-color: rgba(255, 255, 255, 0.02);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-md);
    padding: 16px;
    font-size: 0.85rem;
}

.spec-row {
    display: flex;
    justify-content: space-between;
    padding: 6px 0;
    border-bottom: 1px solid rgba(255, 255, 255, 0.04);
}

.spec-row:last-child {
    border-bottom: none;
}

.spec-label {
    color: var(--text-muted);
}

.spec-val {
    color: var(--text-primary);
    font-weight: 500;
}

.book-detail-right {
    display: flex;
    flex-direction: column;
    justify-content: center;
}

.book-detail-title {
    font-size: 2rem;
    font-weight: 700;
    margin-bottom: 12px;
}

.book-detail-subtitle {
    font-size: 1.15rem;
    color: var(--primary-light);
    font-weight: 500;
    margin-bottom: 24px;
}

.book-detail-description {
    color: var(--text-secondary);
    font-size: 1.05rem;
    margin-bottom: 32px;
}

.book-detail-description p {
    margin-bottom: 16px;
}

.book-detail-highlights {
    margin-bottom: 32px;
}

.highlights-title {
    font-size: 1rem;
    font-weight: 700;
    margin-bottom: 16px;
    color: var(--text-primary);
}

.highlights-list {
    list-style: none;
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 16px;
}

.highlight-item {
    position: relative;
    padding-left: 28px;
    color: var(--text-secondary);
    font-size: 0.95rem;
}

.highlight-item::before {
    content: "✓";
    position: absolute;
    left: 4px;
    top: 0;
    color: var(--primary-light);
    font-weight: 700;
    font-size: 1.1rem;
}

.audience-box {
    background-color: rgba(99, 102, 241, 0.05);
    border: 1px solid rgba(99, 102, 241, 0.15);
    border-radius: var(--radius-md);
    padding: 20px;
    margin-bottom: 32px;
}

.audience-title {
    font-size: 0.95rem;
    font-weight: 700;
    color: var(--primary-light);
    margin-bottom: 8px;
}

.audience-desc {
    font-size: 0.9rem;
    color: var(--text-secondary);
    line-height: 1.6;
}

.book-detail-actions {
    display: flex;
    align-items: center;
    gap: 24px;
}

.book-detail-price-info {
    display: flex;
    flex-direction: column;
}

.book-detail-price-info .price {
    font-size: 1.5rem;
    font-weight: 700;
    color: var(--accent-light);
}

.book-detail-price-info .disclaimer {
    font-size: 0.75rem;
    color: var(--text-muted);
}

/* ==========================================================================
   FAQ 常見問題區
   ========================================================================== */
.faq {
    background-color: var(--bg-dark);
}

.faq-list {
    max-width: 800px;
    margin: 0 auto;
    display: flex;
    flex-direction: column;
    gap: 16px;
}

.faq-item {
    background-color: var(--bg-card);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-md);
    overflow: hidden;
    transition: var(--transition-fast);
}

.faq-item:hover {
    border-color: var(--border-color-hover);
}

.faq-question {
    width: 100%;
    padding: 24px;
    background: none;
    border: none;
    outline: none;
    color: var(--text-primary);
    font-family: var(--font-sans);
    font-size: 1.1rem;
    font-weight: 600;
    text-align: left;
    display: flex;
    justify-content: space-between;
    align-items: center;
    cursor: pointer;
}

.faq-icon {
    font-size: 1.2rem;
    color: var(--text-secondary);
    transition: var(--transition-normal);
}

.faq-item.active .faq-icon {
    transform: rotate(45deg);
    color: var(--primary-light);
}

.faq-answer {
    max-height: 0;
    overflow: hidden;
    transition: max-height var(--transition-normal) ease-out;
    background-color: rgba(0,0,0,0.1);
}

.faq-answer-inner {
    padding: 0 24px 24px 24px;
    color: var(--text-secondary);
    font-size: 0.98rem;
    line-height: 1.7;
}

/* ==========================================================================
   聯盟行銷揭露聲明與 Footer
   ========================================================================== */
.disclosure {
    background-color: rgba(11, 15, 25, 0.9);
    border-top: 1px solid var(--border-color);
    padding: 48px 0;
}

.disclosure-box {
    max-width: 800px;
    margin: 0 auto;
    background-color: rgba(255, 255, 255, 0.01);
    border: 1px dashed var(--border-color);
    border-radius: var(--radius-md);
    padding: 24px;
    text-align: center;
}

.disclosure-title {
    font-size: 0.95rem;
    font-weight: 700;
    color: var(--text-primary);
    margin-bottom: 10px;
}

.disclosure-text {
    font-size: 0.88rem;
    color: var(--text-secondary);
    line-height: 1.6;
}

footer {
    background-color: #080c14;
    border-top: 1px solid rgba(255, 255, 255, 0.04);
    padding: 60px 0 40px 0;
    color: var(--text-muted);
    font-size: 0.9rem;
}

.footer-grid {
    display: grid;
    grid-template-columns: 1.5fr 1fr;
    gap: 48px;
    margin-bottom: 40px;
}

.footer-brand {
    max-width: 400px;
}

.footer-logo {
    font-size: 1.25rem;
    font-weight: 800;
    color: var(--text-primary);
    margin-bottom: 16px;
}

.footer-brand-desc {
    line-height: 1.6;
}

.footer-links-wrap {
    display: flex;
    justify-content: flex-end;
    gap: 80px;
}

.footer-links-col {
    display: flex;
    flex-direction: column;
    gap: 12px;
}

.footer-col-title {
    font-size: 0.85rem;
    font-weight: 700;
    color: var(--text-secondary);
    letter-spacing: 1px;
    margin-bottom: 8px;
}

.footer-link:hover {
    color: var(--text-primary);
}

.footer-bottom {
    border-top: 1px solid rgba(255, 255, 255, 0.04);
    padding-top: 30px;
    display: flex;
    justify-content: space-between;
    align-items: center;
    flex-wrap: wrap;
    gap: 16px;
}

.copyright {
    font-size: 0.8rem;
}

.footer-meta {
    font-size: 0.8rem;
    display: flex;
    gap: 16px;
}

/* ==========================================================================
   響應式排版 (Responsive Design)
   ========================================================================== */

@media (max-width: 1024px) {
    .books-grid {
        grid-template-columns: repeat(2, 1fr);
        gap: 24px;
    }
}

@media (max-width: 900px) {
    .section {
        padding: 80px 0;
    }
    
    .hero {
        padding-top: 140px;
        min-height: auto;
    }
    
    .hero-grid {
        grid-template-columns: 1fr;
        gap: 60px;
        text-align: center;
    }
    
    .hero-content {
        max-width: 100%;
        display: flex;
        flex-direction: column;
        align-items: center;
    }
    
    .hero-badge {
        justify-content: center;
    }
    
    .hero-actions {
        justify-content: center;
    }
    
    .hero-visual {
        height: 380px;
    }
    
    .about-grid {
        grid-template-columns: 1fr;
        gap: 40px;
        text-align: center;
    }
    
    .about-avatar-wrapper {
        margin-bottom: 12px;
    }
    
    .about-info {
        max-width: 100%;
    }
    
    .about-stats {
        max-width: 480px;
        margin: 0 auto;
    }
    
    .book-detail-item {
        grid-template-columns: 1fr;
        gap: 40px;
        margin-bottom: 80px;
        padding-bottom: 60px;
    }
    
    .book-detail-right {
        align-items: center;
        text-align: center;
    }
    
    .highlights-list {
        grid-template-columns: 1fr;
        max-width: 480px;
        margin: 0 auto 32px auto;
        text-align: left;
    }
    
    .audience-box {
        max-width: 480px;
        margin: 0 auto 32px auto;
        text-align: left;
    }
    
    .book-detail-actions {
        flex-direction: column;
        gap: 16px;
        width: 100%;
        max-width: 320px;
        margin: 0 auto;
    }
    
    .book-detail-price-info {
        align-items: center;
    }
    
    .book-detail-actions .btn {
        width: 100%;
    }
    
    .footer-grid {
        grid-template-columns: 1fr;
        gap: 32px;
        text-align: center;
    }
    
    .footer-brand {
        max-width: 100%;
    }
    
    .footer-links-wrap {
        justify-content: center;
        gap: 48px;
    }
    
    .footer-bottom {
        flex-direction: column;
        text-align: center;
    }
}

@media (max-width: 768px) {
    .nav-menu {
        position: fixed;
        top: 80px;
        left: 0;
        right: 0;
        bottom: 0;
        background-color: var(--bg-dark);
        flex-direction: column;
        padding: 40px 24px;
        gap: 24px;
        transform: translateX(100%);
        transition: var(--transition-normal);
        z-index: 99;
        height: calc(100vh - 80px);
        overflow-y: auto;
        border-top: 1px solid var(--border-color);
    }
    
    header.scrolled .nav-menu {
        top: 64px;
        height: calc(100vh - 64px);
    }
    
    .nav-menu.open {
        transform: translateX(0);
    }
    
    .nav-toggle {
        display: block;
    }
    
    .nav-toggle.open span:nth-child(1) {
        transform: translateY(7px) rotate(45deg);
    }
    
    .nav-toggle.open span:nth-child(2) {
        opacity: 0;
    }
    
    .nav-toggle.open span:nth-child(3) {
        transform: translateY(-7px) rotate(-45deg);
    }
    
    .hero-title {
        font-size: 2.5rem;
    }
    
    .section-title {
        font-size: 1.85rem;
    }
    
    .books-grid {
        grid-template-columns: 1fr;
        max-width: 420px;
        margin: 0 auto;
    }
    
    .filter-tabs {
        flex-wrap: wrap;
        justify-content: center;
    }
    
    .filter-tab {
        padding: 6px 14px;
        font-size: 0.88rem;
    }
}