/* 全域樣式設定 */
:root {
    --primary-color: #2c3e50;
    --secondary-color: #3498db;
    --accent-color: #e74c3c;
    --text-color: #333;
    --text-muted: #6c757d;
    --background: #ffffff;
    --background-light: #f8f9fa;
    --border-color: #dee2e6;
    --success-color: #27ae60;
    --warning-color: #f39c12;
    --info-color: #3498db;
    --spacing-xs: 0.25rem;
    --spacing-sm: 0.5rem;
    --spacing-md: 1rem;
    --spacing-lg: 1.5rem;
    --spacing-xl: 2rem;
    --spacing-2xl: 3rem;
    --spacing-3xl: 4rem;
    --border-radius: 0.5rem;
    --transition: all 0.3s ease;
    --shadow-sm: 0 2px 4px rgba(0,0,0,0.1);
    --shadow-md: 0 4px 6px rgba(0,0,0,0.1);
    --shadow-lg: 0 10px 25px rgba(0,0,0,0.1);
}

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

body {
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
    line-height: 1.6;
    color: var(--text-color);
    background-color: var(--background);
}

/* 容器 */
.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 var(--spacing-lg);
}

/* 導航欄 */
.navbar {
    background: var(--primary-color);
    padding: var(--spacing-md) 0;
    position: sticky;
    top: 0;
    z-index: 1000;
    box-shadow: var(--shadow-md);
}

.navbar-content {
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.navbar-brand {
    color: white;
    font-size: 1.25rem;
    font-weight: bold;
}

.navbar-nav {
    display: flex;
    list-style: none;
    gap: var(--spacing-lg);
}

.navbar-nav a {
    color: white;
    text-decoration: none;
    transition: var(--transition);
    padding: var(--spacing-sm) var(--spacing-md);
    border-radius: var(--border-radius);
}

.navbar-nav a:hover {
    background: rgba(255, 255, 255, 0.1);
}

/* 藏書章 logo（navbar / footer brand） */
.brand-seal {
    width: 22px;
    height: 22px;
    vertical-align: -5px;
    margin-right: 8px;
    display: inline-block;
    transform: rotate(-2deg);
    filter: drop-shadow(0 1px 2px rgba(0, 0, 0, 0.25));
    transition: transform 0.3s ease;
}
.brand-seal:hover {
    transform: rotate(-2deg) scale(1.08);
}
.brand-seal--light {
    filter: drop-shadow(0 1px 3px rgba(0, 0, 0, 0.35));
}

/* 英雄區塊 */
.hero {
    background: linear-gradient(135deg, var(--primary-color), var(--secondary-color));
    color: white;
    padding: var(--spacing-3xl) 0;
    text-align: center;
}

.hero h1 {
    font-size: 3rem;
    margin-bottom: var(--spacing-lg);
    animation: fadeInUp 1s ease;
}

.hero p {
    font-size: 1.25rem;
    margin-bottom: var(--spacing-xl);
    opacity: 0.9;
}

/* 按鈕 */
.btn {
    display: inline-block;
    padding: var(--spacing-md) var(--spacing-xl);
    border-radius: var(--border-radius);
    text-decoration: none;
    transition: var(--transition);
    cursor: pointer;
    border: none;
    font-size: 1rem;
}

.btn-primary {
    background: var(--primary-color);
    color: white;
}

.btn-primary:hover {
    background: #1a252f;
    transform: translateY(-2px);
}

.btn-accent {
    background: var(--accent-color);
    color: white;
}

.btn-accent:hover {
    background: #c0392b;
    transform: translateY(-2px);
}

/* 區塊 */
.section {
    padding: var(--spacing-3xl) 0;
}

.section-title {
    text-align: center;
    margin-bottom: var(--spacing-2xl);
}

.section-title h2 {
    font-size: 2.5rem;
    color: var(--primary-color);
    margin-bottom: var(--spacing-md);
}

/* 卡片 */
.card {
    background: white;
    border-radius: var(--border-radius);
    padding: var(--spacing-xl);
    box-shadow: var(--shadow-md);
    transition: var(--transition);
    height: 100%;
}

.card:hover {
    transform: translateY(-5px);
    box-shadow: var(--shadow-lg);
}

.card-icon {
    font-size: 3rem;
    margin-bottom: var(--spacing-md);
}

.card-title {
    font-size: 1.5rem;
    margin-bottom: var(--spacing-md);
    color: var(--primary-color);
}

/* 網格系統 */
.grid {
    display: grid;
    gap: var(--spacing-xl);
}

.grid-2 {
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
}

.grid-3 {
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
}

/* 特色區塊 */
.features {
    background: var(--background-light);
}

.feature-item {
    text-align: center;
    padding: var(--spacing-xl);
}

.feature-icon {
    width: 80px;
    height: 80px;
    margin: 0 auto var(--spacing-lg);
    background: linear-gradient(135deg, var(--primary-color), var(--secondary-color));
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    color: white;
    font-size: 2rem;
}

/* 課程卡片 */
.course-card {
    background: white;
    border-radius: var(--border-radius);
    overflow: hidden;
    box-shadow: var(--shadow-md);
    transition: var(--transition);
}

.course-card:hover {
    transform: translateY(-5px);
    box-shadow: var(--shadow-lg);
}

.course-header {
    background: linear-gradient(135deg, var(--primary-color), var(--secondary-color));
    color: white;
    padding: var(--spacing-xl);
    text-align: center;
}

.course-body {
    padding: var(--spacing-xl);
}

.course-meta {
    display: flex;
    justify-content: space-between;
    margin-bottom: var(--spacing-lg);
    color: var(--text-muted);
    font-size: 0.9rem;
}

/* 章節列表 - 雜誌風格設計 */
.chapter-list {
    list-style: none;
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(285px, 1fr));
    gap: 2rem;
    padding: 2rem 0;
}

/* 雜誌風格章節卡片 */
.chapter-item {
    position: relative;
    background: white;
    border: none;
    border-radius: 12px;
    overflow: hidden;
    transition: all 0.4s cubic-bezier(0.165, 0.84, 0.44, 1);
    cursor: pointer;
    display: flex;
    flex-direction: column;
    text-decoration: none;
    color: inherit;
    box-shadow: 0 4px 6px rgba(0, 0, 0, 0.07), 0 1px 3px rgba(0, 0, 0, 0.06);
    min-height: 220px;
}

.chapter-item::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 4px;
    background: linear-gradient(90deg, var(--primary-color), var(--secondary-color));
    transform: scaleX(0);
    transform-origin: left;
    transition: transform 0.4s ease;
}

.chapter-item:hover {
    transform: translateY(-8px) scale(1.02);
    box-shadow: 0 20px 25px rgba(0, 0, 0, 0.15), 0 10px 10px rgba(0, 0, 0, 0.12);
}

.chapter-item:hover::before {
    transform: scaleX(1);
}

/* 章節編號 - 大號雜誌風格 */
.chapter-number {
    position: absolute;
    top: -10px;
    left: 20px;
    width: 60px;
    height: 60px;
    background: linear-gradient(135deg, var(--primary-color), var(--secondary-color));
    color: white;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 1.5rem;
    font-weight: bold;
    box-shadow: 0 4px 15px rgba(0, 0, 0, 0.2);
    z-index: 2;
}

/* 章節內容區 */
.chapter-content {
    padding: 2rem 1.5rem 1.5rem;
    flex-grow: 1;
    display: flex;
    flex-direction: column;
    margin-left: 50px;
}

/* 章節標題 */
.chapter-title {
    font-size: 1.3rem;
    font-weight: 700;
    color: var(--primary-color);
    margin-bottom: 0.75rem;
    line-height: 1.3;
    letter-spacing: -0.5px;
    display: -webkit-box;
    -webkit-line-clamp: 2;
    line-clamp: 2;
    -webkit-box-orient: vertical;
    overflow: hidden;
}

/* 章節描述 */
.chapter-description {
    color: var(--text-muted);
    font-size: 0.95rem;
    line-height: 1.6;
    flex-grow: 1;
    display: -webkit-box;
    -webkit-line-clamp: 3;
    line-clamp: 3;
    -webkit-box-orient: vertical;
    overflow: hidden;
}

/* 章節狀態標籤 */
.chapter-status {
    position: absolute;
    bottom: 20px;
    right: 20px;
}

.status-badge {
    display: inline-block;
    padding: 0.35rem 0.75rem;
    border-radius: 20px;
    font-size: 0.75rem;
    font-weight: 600;
    text-transform: uppercase;
    letter-spacing: 0.5px;
    background: #f0f0f0;
    color: #999;
    transition: all 0.3s ease;
}

.status-badge[data-status="completed"] {
    background: linear-gradient(135deg, #52c41a, #73d13d);
    color: white;
}

.status-badge[data-status="in-progress"] {
    background: linear-gradient(135deg, #faad14, #ffc53d);
    color: white;
}

.status-badge[data-status="not-started"] {
    background: #f5f5f5;
    color: #bfbfbf;
}

/* 章節底部元信息 */
.chapter-meta {
    padding: 0.75rem 1.5rem;
    background: var(--background-light);
    border-top: 1px solid var(--border-color);
    display: flex;
    justify-content: space-between;
    align-items: center;
    font-size: 0.85rem;
    color: var(--text-muted);
}

/* 特殊章節標記 - 已移除雙倍寬度 */
.chapter-item[data-featured="true"] {
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    color: white;
}

.chapter-item[data-featured="true"] .chapter-title,
.chapter-item[data-featured="true"] .chapter-description {
    color: white;
}

/* 章節分組標題 */
.chapter-group-title {
    grid-column: 1 / -1;
    font-size: 1.1rem;
    font-weight: 600;
    color: var(--primary-color);
    text-transform: uppercase;
    letter-spacing: 2px;
    margin: 2rem 0 1rem;
    padding-bottom: 0.5rem;
    border-bottom: 2px solid var(--primary-color);
    position: relative;
}

.chapter-group-title::after {
    content: '';
    position: absolute;
    bottom: -2px;
    left: 0;
    width: 60px;
    height: 4px;
    background: var(--accent-color);
}

/* 響應式設計 */
@media (max-width: 768px) {
    .chapter-list {
        grid-template-columns: 1fr;
        gap: 1.5rem;
    }
    
    
    .chapter-content {
        margin-left: 30px;
    }
    
    .chapter-number {
        width: 50px;
        height: 50px;
        font-size: 1.25rem;
    }
    
    .chapter-title {
        font-size: 1.1rem;
    }
}

/* 進度條 */
.progress-bar {
    background: var(--border-color);
    height: 8px;
    border-radius: var(--border-radius);
    overflow: hidden;
    margin-bottom: var(--spacing-md);
}

.progress-fill {
    background: linear-gradient(90deg, var(--success-color), var(--info-color));
    height: 100%;
    transition: width 0.5s ease;
}

/* 頁腳 */
.footer {
    background: var(--primary-color);
    color: white;
    padding: var(--spacing-xl) 0;
    margin-top: var(--spacing-3xl);
}

.footer-content {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: var(--spacing-xl);
}

.footer-section h4 {
    margin-bottom: var(--spacing-md);
}

.footer-section ul {
    list-style: none;
}

.footer-section a {
    color: rgba(255, 255, 255, 0.8);
    text-decoration: none;
    transition: var(--transition);
}

.footer-section a:hover {
    color: white;
}

/* 工具類 */
.text-center {
    text-align: center;
}

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

.mb-1 { margin-bottom: var(--spacing-sm); }
.mb-2 { margin-bottom: var(--spacing-md); }
.mb-3 { margin-bottom: var(--spacing-lg); }
.mb-4 { margin-bottom: var(--spacing-xl); }

.mt-1 { margin-top: var(--spacing-sm); }
.mt-2 { margin-top: var(--spacing-md); }
.mt-3 { margin-top: var(--spacing-lg); }
.mt-4 { margin-top: var(--spacing-xl); }

/* 動畫 */
@keyframes fadeInUp {
    from {
        opacity: 0;
        transform: translateY(30px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

.fade-in {
    animation: fadeInUp 0.8s ease;
}

/* 響應式設計 */
@media (max-width: 768px) {
    .hero h1 {
        font-size: 2rem;
    }
    
    .section-title h2 {
        font-size: 1.75rem;
    }
    
    .navbar-nav {
        flex-direction: column;
        gap: var(--spacing-sm);
    }
    
    .grid-3 {
        grid-template-columns: 1fr;
    }
    
    .footer-content {
        grid-template-columns: 1fr;
        text-align: center;
    }
}

/* 麵包屑導航 */
.breadcrumb {
    padding: var(--spacing-md) 0;
    background: var(--background-light);
}

.breadcrumb-list {
    display: flex;
    list-style: none;
    gap: var(--spacing-sm);
    align-items: center;
}

.breadcrumb-item {
    color: var(--text-muted);
}

.breadcrumb-item a {
    color: var(--secondary-color);
    text-decoration: none;
}

.breadcrumb-item a:hover {
    text-decoration: underline;
}

.breadcrumb-separator {
    margin: 0 var(--spacing-sm);
}

/* 內容區塊 */
.content-wrapper {
    max-width: 900px;
    margin: 0 auto;
    padding: var(--spacing-2xl) var(--spacing-lg);
}

.content-section {
    background: white;
    border-radius: var(--border-radius);
    padding: var(--spacing-xl);
    margin-bottom: var(--spacing-xl);
    box-shadow: var(--shadow-sm);
}

.content-section h2 {
    color: var(--primary-color);
    margin-bottom: var(--spacing-lg);
    padding-bottom: var(--spacing-md);
    border-bottom: 2px solid var(--border-color);
}

.content-section h3 {
    color: var(--secondary-color);
    margin-top: var(--spacing-lg);
    margin-bottom: var(--spacing-md);
}

.content-section p {
    margin-bottom: var(--spacing-md);
    line-height: 1.8;
}

/* 提示框 */
.alert {
    padding: var(--spacing-md);
    border-radius: var(--border-radius);
    margin-bottom: var(--spacing-lg);
}

.alert-info {
    background: #e3f2fd;
    border-left: 4px solid var(--info-color);
    color: #1565c0;
}

.alert-success {
    background: #e8f5e9;
    border-left: 4px solid var(--success-color);
    color: #2e7d32;
}

.alert-warning {
    background: #fff3e0;
    border-left: 4px solid var(--warning-color);
    color: #e65100;
}

/* 學習重點 */
.key-points {
    background: var(--background-light);
    border-radius: var(--border-radius);
    padding: var(--spacing-lg);
    margin: var(--spacing-xl) 0;
}

.key-points h3 {
    color: var(--primary-color);
    margin-bottom: var(--spacing-md);
}

.key-points ul {
    list-style: none;
    padding-left: 0;
}

.key-points li {
    padding: var(--spacing-sm) 0;
    padding-left: var(--spacing-xl);
    position: relative;
}

.key-points li:before {
    content: "✓";
    position: absolute;
    left: 0;
    color: var(--success-color);
    font-weight: bold;
}

/* 章節內容卡片 - 現代雜誌風格 */
.chapter-content-card {
    background: white;
    border-radius: 16px;
    padding: 2.5rem;
    margin-bottom: 3rem;
    box-shadow: 0 4px 20px rgba(0, 0, 0, 0.08);
    position: relative;
    overflow: hidden;
}

.chapter-content-card::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    width: 5px;
    height: 100%;
    background: linear-gradient(180deg, var(--primary-color), var(--secondary-color));
}

.chapter-section-number {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    width: 40px;
    height: 40px;
    background: linear-gradient(135deg, var(--primary-color), var(--secondary-color));
    color: white;
    border-radius: 50%;
    font-weight: bold;
    font-size: 1.2rem;
    margin-bottom: 1rem;
    box-shadow: 0 4px 12px rgba(52, 152, 219, 0.3);
}

.chapter-section-title {
    font-size: 1.8rem;
    font-weight: 700;
    color: var(--primary-color);
    margin-bottom: 1.5rem;
    line-height: 1.3;
}

.chapter-content-body {
    font-size: 1.05rem;
    line-height: 1.8;
    color: #4a5568;
}

.chapter-content-body p {
    margin-bottom: 1.2rem;
}

.chapter-content-body h4 {
    color: var(--primary-color);
    font-size: 1.3rem;
    margin-top: 2rem;
    margin-bottom: 1rem;
    padding-bottom: 0.5rem;
    border-bottom: 2px solid #e2e8f0;
}

.chapter-content-body h5 {
    color: var(--secondary-color);
    font-size: 1.1rem;
    margin-top: 1.5rem;
    margin-bottom: 0.8rem;
}

/* 重點提示框 */
.highlight-box {
    background: linear-gradient(135deg, #f0f9ff 0%, #e0f2fe 100%);
    border-left: 4px solid var(--secondary-color);
    padding: 1.5rem;
    margin: 2rem 0;
    border-radius: 8px;
}

.highlight-box h5 {
    color: var(--secondary-color);
    margin-bottom: 0.8rem;
    font-size: 1.1rem;
    display: flex;
    align-items: center;
}

/* 案例框 */
.case-study-box {
    background: #f0fdf4;
    border: 2px solid #86efac;
    border-radius: 12px;
    padding: 1.5rem;
    margin: 2rem 0;
}

.case-study-box h5 {
    color: #16a34a;
    margin-bottom: 1rem;
    font-size: 1.1rem;
}

.case-study-box h5::before {
    content: '📖 ';
    margin-right: 0.5rem;
}

/* 閱讀進度指示器 */
.reading-progress {
    position: fixed;
    top: 60px;
    left: 0;
    width: 100%;
    height: 4px;
    background: #e2e8f0;
    z-index: 999;
}

.reading-progress-bar {
    height: 100%;
    background: linear-gradient(90deg, var(--primary-color), var(--secondary-color));
    width: 0%;
    transition: width 0.2s ease;
}

/* 側邊導航 */
.side-nav {
    position: fixed;
    right: 30px;
    top: 50%;
    transform: translateY(-50%);
    z-index: 100;
}

.side-nav-item {
    display: block;
    width: 12px;
    height: 12px;
    background: #cbd5e1;
    border-radius: 50%;
    margin: 20px 0;
    transition: all 0.3s ease;
    cursor: pointer;
    position: relative;
}

.side-nav-item:hover {
    background: var(--secondary-color);
    transform: scale(1.5);
}

.side-nav-item.active {
    background: var(--primary-color);
    transform: scale(1.5);
}

.side-nav-item::before {
    content: attr(data-title);
    position: absolute;
    right: 25px;
    top: 50%;
    transform: translateY(-50%);
    background: var(--primary-color);
    color: white;
    padding: 0.3rem 0.8rem;
    border-radius: 6px;
    font-size: 0.85rem;
    white-space: nowrap;
    opacity: 0;
    pointer-events: none;
    transition: opacity 0.3s ease;
}

.side-nav-item:hover::before {
    opacity: 1;
}

/* 第4章專用側邊導航 */
.side-nav.nav-ch {
    right: clamp(8px, calc((100vw - 1200px) / 2 + 24px), 96px);
    top: calc(50% + 24px);
    transform: translateY(-50%);
    display: flex;
    flex-direction: column;
    align-items: flex-end;
    gap: 0.45rem;
    width: auto;
    z-index: 1105;
}

.side-nav.nav-ch .nav-ch-toggle {
    border: none;
    background: transparent;
    color: #f97316;
    box-shadow: none;
    display: flex;
    align-items: center;
    justify-content: center;
    cursor: pointer;
    padding: 0.15rem 0.35rem;
    font-size: 2rem;
    font-weight: 700;
    line-height: 1;
    transition: color 0.2s ease, transform 0.2s ease;
}

.side-nav.nav-ch .nav-ch-toggle:hover {
    transform: translateX(-2px);
    color: #fb923c;
}

.side-nav.nav-ch .nav-ch-toggle:focus-visible {
    outline: 3px solid rgba(249, 115, 22, 0.35);
    outline-offset: 2px;
}

.side-nav.nav-ch .toggle-icon {
    font-size: 1em;
    line-height: 1;
}

.side-nav.nav-ch .nav-ch-list {
    list-style: none;
    margin: 0;
    padding: 0.45rem 0.55rem 0.45rem 0.48rem;
    border-radius: 16px;
    background: rgba(255, 255, 255, 0.96);
    box-shadow: 0 16px 32px rgba(15, 23, 42, 0.16);
    display: flex;
    flex-direction: column;
    gap: 0.25rem;
    width: 200px;
    overflow: visible;
    backdrop-filter: blur(8px);
    transition: width 0.3s ease, padding 0.3s ease;
}

.side-nav.nav-ch .nav-ch-list::-webkit-scrollbar {
    width: 6px;
}

.side-nav.nav-ch .nav-ch-list::-webkit-scrollbar-thumb {
    background: rgba(148, 163, 184, 0.6);
    border-radius: 999px;
}

.side-nav.nav-ch .nav-ch-item {
    display: flex;
    align-items: center;
    gap: 0.48rem;
    padding: 0.52rem 0.68rem;
    border-radius: 10px;
    text-decoration: none;
    color: #1f2937;
    font-weight: 600;
    letter-spacing: 0.01em;
    position: relative;
    transition: background 0.3s ease, transform 0.2s ease, color 0.3s ease, box-shadow 0.3s ease;
}

.side-nav.nav-ch .nav-ch-item:hover {
    background: #fff7ed;
    transform: translateX(-2px);
}

.side-nav.nav-ch .nav-ch-item:not(.nav-ch-item--quiz):hover .nav-ch-indicator {
    background: #fdba74;
}

.side-nav.nav-ch .nav-ch-item .nav-ch-indicator {
    width: 12px;
    height: 12px;
    border-radius: 50%;
    background: #fed7aa;
    box-shadow: 0 0 0 0 rgba(249, 115, 22, 0.15);
    transition: transform 0.3s ease, background 0.3s ease, box-shadow 0.3s ease;
    flex-shrink: 0;
}

.side-nav.nav-ch .nav-ch-item .nav-ch-label {
    font-size: 0.9rem;
    white-space: nowrap;
}

.side-nav.nav-ch .nav-ch-item.is-active {
    background: #fff1e6;
    color: #9a3412;
    box-shadow: inset 0 0 0 1px #fdba74;
}

.side-nav.nav-ch .nav-ch-item.is-active .nav-ch-indicator {
    background: #f97316;
    transform: scale(1.25);
    box-shadow: 0 4px 10px rgba(249, 115, 22, 0.35);
}

.side-nav.nav-ch .nav-ch-item--quiz {
    background: linear-gradient(135deg, #1d4ed8, #2563eb);
    color: #fff;
}

.side-nav.nav-ch .nav-ch-item--quiz .nav-ch-indicator {
    background: rgba(191, 219, 254, 0.65);
}

.side-nav.nav-ch .nav-ch-item--quiz:hover {
    background: linear-gradient(135deg, #1e40af, #1d4ed8);
}

.side-nav.nav-ch .nav-ch-item--quiz.is-active {
    box-shadow: inset 0 0 0 1px rgba(191, 219, 254, 0.5);
}

.side-nav.nav-ch .nav-ch-item--quiz.is-active .nav-ch-indicator {
    background: #38bdf8;
}

/* Sub-nav items */
.nav-ch-sublist {
    list-style: none;
    padding: 0.15rem 0 0.15rem 1.35rem;
    margin: 0;
}

.nav-ch-subitem {
    display: block;
    padding: 0.2rem 0.5rem;
    font-size: 0.75rem;
    color: #6b7280;
    text-decoration: none;
    border-left: 2px solid #e5e7eb;
    transition: color 0.15s, border-color 0.15s;
}

.nav-ch-subitem:hover {
    color: #4f46e5;
    border-left-color: #a5b4fc;
}

.side-nav.nav-ch.collapsed .nav-ch-sublist {
    display: none;
}


.side-nav.nav-ch.collapsed .nav-ch-list {
    width: 26px;
    padding: 0.55rem 0.3rem;
    border-radius: 999px;
}

.side-nav.nav-ch.collapsed .nav-ch-item {
    justify-content: center;
    padding: 0.35rem 0;
    background: transparent !important;
    box-shadow: none !important;
    transform: none !important;
    color: #1f2937;
}

.side-nav.nav-ch.collapsed .nav-ch-item .nav-ch-label {
    display: none;
}

.side-nav.nav-ch.collapsed .nav-ch-item .nav-ch-indicator {
    width: 12px;
    height: 12px;
    margin-right: 0;
    transform: none;
    background: #cbd5e1;
}

.side-nav.nav-ch.collapsed .nav-ch-item.is-active .nav-ch-indicator {
    transform: scale(1.3);
    background: #f97316;
}

.side-nav.nav-ch.collapsed .nav-ch-item.nav-ch-item--quiz .nav-ch-indicator {
    background: rgba(191, 219, 254, 0.75);
}

.side-nav.nav-ch.collapsed .nav-ch-item.nav-ch-item--quiz.is-active .nav-ch-indicator {
    background: #2563eb;
}

.side-nav.nav-ch.collapsed .nav-ch-item::after {
    content: attr(data-title);
    position: absolute;
    left: calc(100% + 10px);
    top: 50%;
    transform: translateY(-50%);
    background: rgba(30, 41, 59, 0.95);
    color: #fff;
    padding: 0.35rem 0.7rem;
    border-radius: 8px;
    font-size: 0.85rem;
    white-space: nowrap;
    opacity: 0;
    pointer-events: none;
    transition: opacity 0.2s ease;
}

.side-nav.nav-ch.collapsed .nav-ch-item:hover::after {
    opacity: 1;
}

.side-nav.nav-ch.collapsed .nav-ch-toggle {
    border-radius: 0;
}

.nav-ch-offset {
    position: relative;
}

@media (min-width: 1100px) {
    .nav-ch-offset {
        padding-right: calc(130px + 1rem);
    }
}

@media (max-width: 1280px) {
    .side-nav.nav-ch .nav-ch-list {
        width: 130px;
    }
}

/* 內容列表 */
.content-list {
    list-style: none;
    padding-left: 0;
}

.content-list li {
    position: relative;
    padding-left: 2rem;
    margin-bottom: 1rem;
    line-height: 1.6;
}

.content-list li::before {
    content: '▸';
    position: absolute;
    left: 0;
    color: var(--secondary-color);
    font-weight: bold;
}

/* 關鍵概念卡片 */
.key-concept-card {
    background: linear-gradient(135deg, #fef3c7 0%, #fde68a 100%);
    border-radius: 12px;
    padding: 1.5rem;
    margin: 2rem 0;
}

.key-concept-card h5 {
    color: #d97706;
    margin-bottom: 1rem;
    font-size: 1.1rem;
}

.key-concept-card h5::before {
    content: '🔑 ';
    margin-right: 0.5rem;
}

/* 響應式設計 */
@media (max-width: 1024px) {
    .side-nav {
        display: none;
    }
}

@media (max-width: 768px) {
    .chapter-content-card {
        padding: 1.5rem;
        margin-bottom: 2rem;
    }
    
    .chapter-section-title {
        font-size: 1.5rem;
    }
    
    .chapter-content-body {
        font-size: 1rem;
    }
}

/* 問卷表單樣式 */
.form-group {
    margin-bottom: var(--spacing-lg);
}

.form-label {
    display: block;
    margin-bottom: var(--spacing-sm);
    font-weight: 600;
    color: var(--text-primary);
}

.form-control {
    width: 100%;
    max-width: 200px;
    padding: var(--spacing-sm);
    border: 2px solid #e2e8f0;
    border-radius: 8px;
    font-size: 1rem;
    transition: border-color 0.3s ease;
}

.form-control:focus {
    outline: none;
    border-color: var(--primary-color);
    box-shadow: 0 0 0 3px rgba(59, 130, 246, 0.1);
}

.form-text {
    font-size: 0.875rem;
    color: var(--text-secondary);
    margin-top: var(--spacing-xs);
}

/* 李克特量表樣式 */
.likert-scale-legend {
    display: flex;
    justify-content: space-between;
    align-items: center;
    background: var(--background-light);
    padding: var(--spacing-md);
    border-radius: 8px;
    border: 1px solid #e2e8f0;
}

.likert-legend-item {
    display: flex;
    align-items: center;
    gap: var(--spacing-sm);
}

.likert-number {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    width: 32px;
    height: 32px;
    background: var(--primary-color);
    color: white;
    border-radius: 50%;
    font-weight: 600;
    font-size: 0.9rem;
}

.likert-text {
    font-weight: 600;
    color: var(--text-primary);
}

.likert-questions {
    display: flex;
    flex-direction: column;
    gap: var(--spacing-xl);
}

.likert-question {
    padding: var(--spacing-lg);
    background: white;
    border: 1px solid #e2e8f0;
    border-radius: 12px;
    box-shadow: 0 2px 4px rgba(0, 0, 0, 0.05);
}

.question-text {
    margin-bottom: var(--spacing-md);
    font-weight: 500;
    color: var(--text-primary);
    line-height: 1.6;
}

.likert-scale {
    display: flex;
    align-items: center;
    gap: var(--spacing-md);
    flex-wrap: wrap;
}

.scale-label {
    font-size: 0.875rem;
    font-weight: 500;
    color: var(--text-secondary);
    white-space: nowrap;
}

.scale-options {
    display: flex;
    gap: var(--spacing-sm);
    flex-wrap: wrap;
}

.scale-options label {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 4px;
    cursor: pointer;
    padding: var(--spacing-sm);
    border-radius: 8px;
    transition: background-color 0.3s ease;
    font-size: 0.875rem;
    font-weight: 500;
    color: var(--text-secondary);
}

.scale-options label:hover {
    background-color: var(--background-light);
}

.scale-options input[type="radio"] {
    margin: 0;
    width: 20px;
    height: 20px;
    accent-color: var(--primary-color);
}

.scale-options label:has(input:checked) {
    background-color: var(--primary-color);
    color: white;
    border-radius: 8px;
}

/* 質性問卷樣式 */
.qualitative-question {
    margin-bottom: var(--spacing-xl);
}

.question-label {
    display: block;
    margin-bottom: var(--spacing-md);
    font-weight: 500;
    color: var(--text-primary);
    line-height: 1.6;
}

.form-textarea {
    width: 100%;
    min-height: 120px;
    padding: var(--spacing-md);
    border: 2px solid #e2e8f0;
    border-radius: 8px;
    font-size: 1rem;
    line-height: 1.5;
    resize: vertical;
    transition: border-color 0.3s ease;
    font-family: inherit;
}

.form-textarea:focus {
    outline: none;
    border-color: var(--primary-color);
    box-shadow: 0 0 0 3px rgba(59, 130, 246, 0.1);
}

.form-textarea::placeholder {
    color: var(--text-secondary);
}

/* 提交按鈕樣式 */
.btn-lg {
    padding: var(--spacing-md) var(--spacing-xl);
    font-size: 1.125rem;
    min-width: 160px;
}

/* 響應式調整 */
@media (max-width: 768px) {
    .likert-scale {
        flex-wrap: nowrap;
        align-items: center;
        gap: var(--spacing-xs);
    }
    
    .scale-label {
        font-size: 0.75rem;
        min-width: 60px;
        flex-shrink: 0;
        text-align: center;
    }
    
    .scale-options {
        justify-content: center;
        gap: var(--spacing-xs);
        flex-shrink: 1;
    }
    
    .scale-options label {
        font-size: 0.8rem;
        padding: 0.25rem;
    }
    
    .likert-scale-legend {
        padding: var(--spacing-sm);
        gap: var(--spacing-xs);
    }
    
    .likert-legend-item {
        gap: var(--spacing-xs);
    }
    
    .likert-number {
        width: 24px;
        height: 24px;
        font-size: 0.75rem;
    }
    
    .likert-text {
        font-size: 0.75rem;
    }
}

/* 極小螢幕優化 */
@media (max-width: 480px) {
    .likert-scale {
        gap: 0.125rem;
    }
    
    .scale-label {
        font-size: 0.7rem;
        min-width: 45px;
    }
    
    .scale-options {
        gap: 0.125rem;
    }
    
    .scale-options label {
        font-size: 0.75rem;
        padding: 0.2rem;
    }
    
    .likert-number {
        width: 20px;
        height: 20px;
        font-size: 0.7rem;
    }
    
    .likert-text {
        font-size: 0.7rem;
    }
}

/* 第5章：研究計畫書特定樣式 */
.example-box {
    border-radius: 8px;
    padding: 1.5rem;
    margin: 1.5rem 0;
    border: 1px solid #e5e7eb;
}

.example-box.success {
    background: linear-gradient(135deg, #f0fdf4 0%, #dcfce7 100%);
    border-color: #bbf7d0;
}

.example-box.warning {
    background: linear-gradient(135deg, #fef3c7 0%, #fde68a 100%);
    border-color: #fcd34d;
}

.tab-container {
    margin: 2rem 0;
}

.tab-buttons {
    display: flex;
    border-bottom: 2px solid #e5e7eb;
    margin-bottom: 1.5rem;
    flex-wrap: wrap;
    gap: 0.5rem;
}

.tab-button {
    padding: 0.75rem 1rem;
    background: transparent;
    border: none;
    cursor: pointer;
    font-weight: 500;
    color: #6b7280;
    border-bottom: 2px solid transparent;
    transition: all 0.2s ease;
    font-family: inherit;
}

.tab-button.active {
    color: var(--primary-color);
    border-bottom-color: var(--primary-color);
}

.tab-button:hover:not(.active) {
    color: #374151;
}

.tab-content {
    display: none;
}

.tab-content.active {
    display: block;
}

.cars-step {
    margin: 2rem 0;
    border-left: 4px solid var(--primary-color);
    padding-left: 1.5rem;
}

.cars-step h3 {
    color: var(--primary-color);
    margin-bottom: 1rem;
}

.cars-content {
    margin-top: 1rem;
}

.thinking-box {
    background: linear-gradient(135deg, #f0f9ff 0%, #e0f2fe 100%);
    border: 1px solid #bae6fd;
    border-radius: 8px;
    padding: 1rem;
    margin: 1rem 0;
}

.method-pillars {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 1.5rem;
    margin: 2rem 0;
}

.method-pillar {
    background: var(--background-light);
    border: 1px solid #e5e7eb;
    border-radius: 8px;
    padding: 1.5rem;
}

.method-pillar h4 {
    color: var(--primary-color);
    margin-bottom: 0.75rem;
}

.method-example {
    background: #ffffff;
    border: 1px solid #e5e7eb;
    border-radius: 8px;
    padding: 1.5rem;
    margin: 1.5rem 0;
}


.method-detail {
    margin-bottom: 1.5rem;
}

.method-detail:last-child {
    margin-bottom: 0;
}

.scenario-box {
    background: #ffffff;
    border: 1px solid #e5e7eb;
    border-radius: 8px;
    padding: 1.5rem;
    margin: 1.5rem 0;
}

.scenario-box h4 {
    color: var(--primary-color);
    margin-bottom: 1rem;
}

.proposal-form {
    background: #ffffff;
    border: 1px solid #e5e7eb;
    border-radius: 8px;
    padding: 2rem;
    margin: 2rem 0;
}

.form-group {
    margin-bottom: 1.5rem;
}

.form-group label {
    display: block;
    font-weight: 500;
    margin-bottom: 0.5rem;
    color: #374151;
}

.form-group input,
.form-group textarea {
    width: 100%;
    padding: 0.75rem;
    border: 1px solid #d1d5db;
    border-radius: 6px;
    font-size: 1rem;
    font-family: inherit;
}

.form-group input:focus,
.form-group textarea:focus {
    outline: none;
    border-color: var(--primary-color);
    box-shadow: 0 0 0 3px rgba(59, 130, 246, 0.1);
}

.form-actions {
    display: flex;
    gap: 1rem;
    flex-wrap: wrap;
}

.chart-container {
    position: relative;
    height: 350px;
    margin: 2rem 0;
}

.chart-caption {
    text-align: center;
    color: #6b7280;
    font-size: 0.875rem;
    margin-top: 0.5rem;
}

/* 響應式設計 - 第5章 */
@media (max-width: 768px) {
    .tab-buttons {
        justify-content: center;
    }
    
    .method-pillars {
        grid-template-columns: 1fr;
    }
    
    .form-actions {
        flex-direction: column;
    }
    
    .cars-step {
        padding-left: 1rem;
    }
    
    .proposal-form {
        padding: 1rem;
    }
}

/* ====== Chapter 6: RCT 專用樣式 ====== */

/* 標籤切換 */
.tab-container {
    margin: 2rem 0;
}

.tab-buttons {
    display: flex;
    gap: 0.5rem;
    margin-bottom: 1.5rem;
    padding: 0.25rem;
    background: #f1f5f9;
    border-radius: 0.75rem;
}

.tab-btn {
    flex: 1;
    padding: 0.75rem 1rem;
    font-size: 0.875rem;
    font-weight: 500;
    color: #64748b;
    background: transparent;
    border: none;
    border-radius: 0.5rem;
    cursor: pointer;
    transition: all 0.3s ease;
    text-align: center;
}

.tab-btn:hover {
    color: #0f766e;
    background: rgba(15, 118, 110, 0.1);
}

.tab-btn.active {
    color: white;
    background: #0f766e;
    box-shadow: 0 2px 4px rgba(15, 118, 110, 0.2);
}

.tab-content {
    background: white;
    padding: 2rem;
    border-radius: 0.75rem;
    box-shadow: 0 4px 6px -1px rgba(0, 0, 0, 0.1);
    min-height: 400px;
}

.tab-content.hidden {
    display: none;
}

/* 品質評估指標 */
.quality-metrics-grid {
    display: grid;
    gap: 1.5rem;
    margin: 2rem 0;
}

@media (min-width: 768px) {
    .quality-metrics-grid {
        grid-template-columns: repeat(3, 1fr);
    }
}

.quality-metric-card {
    background: #f8fafc;
    padding: 1.5rem;
    border-radius: 0.75rem;
    border-left: 4px solid #0f766e;
}

.quality-metric-card h4 {
    color: #0f766e;
    font-size: 1.125rem;
    font-weight: bold;
    margin-bottom: 1rem;
}

.quality-metric-card ul {
    list-style: none;
    padding: 0;
}

.quality-metric-card li {
    padding: 0.5rem 0;
    border-bottom: 1px solid #e2e8f0;
}

.quality-metric-card li:last-child {
    border-bottom: none;
}

.quality-metric-card li strong {
    color: #1e293b;
}

/* 設計類型卡片 */
.design-types-container {
    display: grid;
    gap: 2rem;
    margin: 2rem 0;
}

@media (min-width: 768px) {
    .design-types-container {
        grid-template-columns: repeat(2, 1fr);
    }
}

.design-type-card {
    background: white;
    border: 1px solid #e2e8f0;
    border-radius: 0.75rem;
    padding: 1.5rem;
    box-shadow: 0 2px 4px rgba(0, 0, 0, 0.1);
    transition: all 0.3s ease;
}

.design-type-card:hover {
    box-shadow: 0 8px 15px rgba(0, 0, 0, 0.1);
    transform: translateY(-2px);
}

.design-type-card h4 {
    color: #0f766e;
    font-size: 1.25rem;
    font-weight: bold;
    margin-bottom: 0.75rem;
}

.design-description {
    color: #64748b;
    margin-bottom: 1.5rem;
    line-height: 1.6;
}

.pros-cons {
    display: grid;
    gap: 1rem;
    margin: 1.5rem 0;
}

@media (min-width: 640px) {
    .pros-cons {
        grid-template-columns: repeat(2, 1fr);
    }
}

.pros, .cons {
    padding: 1rem;
    border-radius: 0.5rem;
}

.pros {
    background: #f0fdf4;
    border-left: 4px solid #22c55e;
}

.cons {
    background: #fef2f2;
    border-left: 4px solid #ef4444;
}

.pros h6 {
    color: #16a34a;
    font-weight: bold;
    margin-bottom: 0.5rem;
}

.cons h6 {
    color: #dc2626;
    font-weight: bold;
    margin-bottom: 0.5rem;
}

.pros ul, .cons ul {
    list-style: none;
    padding: 0;
}

.pros li, .cons li {
    padding: 0.25rem 0;
    font-size: 0.875rem;
}

.pros li {
    color: #15803d;
}

.cons li {
    color: #b91c1c;
}

.example-box {
    background: #dbeafe;
    border-left: 4px solid #3b82f6;
    padding: 1rem;
    border-radius: 0.5rem;
    margin-top: 1rem;
}

.example-box strong {
    color: #1e40af;
}

/* 應用場景網格 */
.application-scenarios-grid {
    display: grid;
    gap: 2rem;
    margin: 2rem 0;
}

@media (min-width: 768px) {
    .application-scenarios-grid {
        grid-template-columns: repeat(2, 1fr);
    }
}

.scenario-card {
    background: white;
    border: 1px solid #e2e8f0;
    border-radius: 0.75rem;
    padding: 1.5rem;
    box-shadow: 0 2px 4px rgba(0, 0, 0, 0.1);
}

.scenario-card h4 {
    color: #0f766e;
    font-size: 1.25rem;
    font-weight: bold;
    margin-bottom: 0.75rem;
}

.scenario-description {
    color: #64748b;
    margin-bottom: 1.5rem;
    line-height: 1.6;
}

.example-study {
    background: #f0fdfa;
    padding: 1rem;
    border-radius: 0.5rem;
    margin: 1rem 0;
    border-left: 4px solid #14b8a6;
}

.example-study h6 {
    color: #0f766e;
    font-weight: bold;
    margin-bottom: 0.5rem;
}

.example-study ul {
    list-style: disc;
    padding-left: 1.5rem;
    color: #065f46;
}

.example-study li {
    margin: 0.25rem 0;
    font-size: 0.875rem;
}

.key-considerations {
    background: #f8fafc;
    padding: 1rem;
    border-radius: 0.5rem;
    border-left: 4px solid #64748b;
}

.key-considerations h6 {
    color: #334155;
    font-weight: bold;
    margin-bottom: 0.5rem;
}

.key-considerations ul {
    list-style: disc;
    padding-left: 1.5rem;
    color: #475569;
}

.key-considerations li {
    margin: 0.25rem 0;
    font-size: 0.875rem;
}

/* CONSORT 流程圖 */
.consort-flow-container {
    display: grid;
    gap: 2rem;
    margin: 2rem 0;
}

@media (min-width: 1024px) {
    .consort-flow-container {
        grid-template-columns: 1fr 1fr;
    }
}

.flow-left {
    display: flex;
    flex-direction: column;
    gap: 0.5rem;
}

.flow-item {
    padding: 1rem;
    border: 2px solid #e2e8f0;
    border-radius: 0.75rem;
    background: white;
    cursor: pointer;
    transition: all 0.3s ease;
    text-align: center;
}

.flow-item:hover {
    border-color: #0f766e;
    background: #f0fdfa;
}

.flow-item.active {
    border-color: #0f766e;
    background: #f0fdfa;
    transform: translateY(-2px);
    box-shadow: 0 10px 15px -3px rgba(0, 0, 0, 0.1);
}

.flow-step-title {
    font-weight: bold;
    color: #1e293b;
    margin-bottom: 0.25rem;
}

.flow-step-desc {
    font-size: 0.875rem;
    color: #64748b;
}

.flow-arrow {
    text-align: center;
    font-size: 1.5rem;
    color: #94a3b8;
    padding: 0.5rem 0;
}

.flow-details {
    background: #f8fafc;
    padding: 2rem;
    border-radius: 0.75rem;
    min-height: 300px;
}

/* 總結亮點 */
.summary-highlights {
    display: grid;
    gap: 1.5rem;
    margin: 2rem 0;
}

@media (min-width: 768px) {
    .summary-highlights {
        grid-template-columns: repeat(3, 1fr);
    }
}

.highlight-item {
    background: #f0fdfa;
    padding: 1.5rem;
    border-radius: 0.75rem;
    border-left: 4px solid #14b8a6;
}

.highlight-item h4 {
    color: #0f766e;
    font-weight: bold;
    margin-bottom: 1rem;
}

.highlight-item ul {
    list-style: none;
    padding: 0;
}

.highlight-item li {
    margin: 0.75rem 0;
    color: #065f46;
    line-height: 1.5;
}

.key-takeaway {
    background: linear-gradient(135deg, #f0fdfa 0%, #ecfdf5 100%);
    padding: 2rem;
    border-radius: 0.75rem;
    border: 1px solid #14b8a6;
    margin: 2rem 0;
}

.key-takeaway h4 {
    color: #0f766e;
    font-size: 1.25rem;
    font-weight: bold;
    margin-bottom: 1rem;
}

.key-takeaway p {
    color: #065f46;
    line-height: 1.6;
}

/* 練習題樣式 */
.practice-questions {
    display: flex;
    flex-direction: column;
    gap: 1.5rem;
}

.question-card {
    background: white;
    border: 1px solid #e2e8f0;
    border-radius: 0.75rem;
    padding: 1.5rem;
    box-shadow: 0 2px 4px rgba(0, 0, 0, 0.1);
}

.question-title {
    color: #0f766e;
    font-size: 1.125rem;
    font-weight: bold;
    margin-bottom: 0.75rem;
}

.question-content {
    color: #374151;
    line-height: 1.6;
}

/* 模態框樣式增強 */
.modal-overlay {
    position: fixed;
    inset: 0;
    background: rgba(0, 0, 0, 0.5);
    display: flex;
    align-items: center;
    justify-content: center;
    z-index: 50;
    padding: 1rem;
    opacity: 0;
    visibility: hidden;
    transition: all 0.3s ease;
}

.modal-overlay.show {
    opacity: 1;
    visibility: visible;
}

.modal-content {
    background: white;
    border-radius: 0.75rem;
    box-shadow: 0 20px 25px -5px rgba(0, 0, 0, 0.1);
    max-width: 32rem;
    width: 100%;
    padding: 2rem;
    transform: scale(0.95);
    transition: transform 0.3s ease;
}

.modal-overlay.show .modal-content {
    transform: scale(1);
}

.modal-title {
    color: #1e293b;
    font-size: 1.25rem;
    font-weight: bold;
    margin-bottom: 1rem;
}

.modal-body {
    color: #475569;
    line-height: 1.6;
    margin-bottom: 1.5rem;
}

.modal-buttons {
    display: flex;
    justify-content: flex-end;
}

/* 響應式設計 - Chapter 6 */
@media (max-width: 768px) {
    .tab-buttons {
        flex-direction: column;
    }
    
    .quality-metrics-grid {
        grid-template-columns: 1fr;
    }
    
    .design-types-container {
        grid-template-columns: 1fr;
    }
    
    .application-scenarios-grid {
        grid-template-columns: 1fr;
    }
    
    .summary-highlights {
        grid-template-columns: 1fr;
    }
    
    .consort-flow-container {
        grid-template-columns: 1fr;
    }
    
    .pros-cons {
        grid-template-columns: 1fr;
    }
}

/* 文獻引用框 */
.reference-box {
    background: #f0f9ff;
    border: 1px solid #0ea5e9;
    border-left: 4px solid #0ea5e9;
    border-radius: 0.5rem;
    padding: 1rem;
    margin: 1.5rem 0;
}

.reference-box h5 {
    color: #0369a1;
    font-weight: bold;
    margin-bottom: 0.5rem;
}

.reference-box p {
    color: #075985;
    line-height: 1.5;
    margin: 0;
}

.doi-link {
    color: #0369a1;
    text-decoration: underline;
    font-weight: 500;
    transition: var(--transition);
}

.doi-link:hover {
    color: #0284c7;
    text-decoration: none;
}

/* 摘要點樣式更新 */
.summary-emoji {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    width: 2rem;
    height: 2rem;
    font-size: 1.2rem;
    margin-right: 0.75rem;
    flex-shrink: 0;
}

/* === Prompt Copy Button (一鍵複製提示詞) === */
.prompt-copy-btn {
    position: absolute;
    top: 0.55rem;
    right: 0.55rem;
    display: inline-flex;
    align-items: center;
    gap: 5px;
    background: rgba(255, 255, 255, 0.94);
    border: 1px solid rgba(0, 0, 0, 0.08);
    border-radius: 6px;
    padding: 4px 10px;
    font-size: 0.78rem;
    font-weight: 600;
    color: #475569;
    cursor: pointer;
    opacity: 0;
    transition: opacity 0.18s ease, background 0.18s ease, color 0.18s ease, box-shadow 0.18s ease;
    z-index: 5;
    user-select: none;
    line-height: 1;
}
.prompt-copy-btn:hover {
    background: #ffffff;
    color: #0f172a;
    box-shadow: 0 2px 6px rgba(0, 0, 0, 0.10);
}
.prompt-copy-btn:focus-visible {
    outline: 2px solid #3b82f6;
    outline-offset: 1px;
}
.prompt-copy-btn.copied {
    background: #10b981;
    border-color: #059669;
    color: #ffffff;
    opacity: 1 !important;
}
.prompt-copy-btn.failed {
    background: #ef4444;
    border-color: #dc2626;
    color: #ffffff;
    opacity: 1 !important;
}

/* hover 提示詞區塊時顯示按鈕 */
.pv-prompt:hover > .prompt-copy-btn,
.play-prompt:hover > .prompt-copy-btn,
.tech-prompt:hover > .prompt-copy-btn,
.demo-prompt:hover > .prompt-copy-btn,
.ho-prompt:hover > .prompt-copy-btn,
.demo-cmd:hover > .prompt-copy-btn,
.prompt-copy-btn:focus,
.prompt-copy-btn:focus-visible {
    opacity: 1;
}

/* 觸控裝置沒 hover，預設淡淡顯示 */
@media (hover: none) {
    .prompt-copy-btn {
        opacity: 0.85;
    }
}

/* === Heading 內 FontAwesome icon 與文字保持間距 === */
h2 > i[class^="fa-"]:first-child,
h3 > i[class^="fa-"]:first-child,
h4 > i[class^="fa-"]:first-child,
h5 > i[class^="fa-"]:first-child,
h6 > i[class^="fa-"]:first-child {
    margin-right: 0.45rem;
}

/* === 章節間導覽 (chapter pagination) === */
.chapter-pagination {
    display: grid;
    grid-template-columns: 1fr auto 1fr;
    gap: 0.85rem;
    margin: 2.75rem auto 1.25rem;
    padding: 0 1rem;
    max-width: 1100px;
    align-items: stretch;
}
.chapter-pagination > a {
    background: white;
    border: 1px solid #e2e8f0;
    border-radius: 12px;
    padding: 1rem 1.25rem;
    text-decoration: none;
    color: inherit;
    transition: transform 0.25s ease, box-shadow 0.25s ease, border-color 0.25s ease, background 0.25s ease;
    display: flex;
    flex-direction: column;
    justify-content: center;
    box-shadow: 0 2px 6px rgba(0, 0, 0, 0.04);
    min-height: 70px;
}
.chapter-pagination > a:hover {
    background: #faf5ff;
    border-color: #a855f7;
    transform: translateY(-2px);
    box-shadow: 0 6px 18px rgba(124, 58, 237, 0.12);
}
.chapter-pagination .page-direction {
    font-size: 0.75rem;
    color: #64748b;
    font-weight: 700;
    margin-bottom: 0.35rem;
    letter-spacing: 0.5px;
}
.chapter-pagination .page-title {
    font-size: 0.98rem;
    color: #1e293b;
    font-weight: 700;
    line-height: 1.4;
}
.chapter-pagination .page-prev { text-align: left; }
.chapter-pagination .page-next { text-align: right; }
.chapter-pagination .page-toc {
    flex-direction: row;
    align-items: center;
    justify-content: center;
    gap: 0.5rem;
    background: #f8fafc;
    color: #475569;
    padding: 0.9rem 1.4rem;
    font-weight: 600;
    font-size: 0.9rem;
    min-width: 110px;
}
.chapter-pagination .page-toc i {
    color: #64748b;
}
.chapter-pagination .page-toc:hover {
    background: #f1f5f9;
    color: #1e293b;
}
.chapter-pagination .page-toc:hover i {
    color: #1e293b;
}

@media (max-width: 720px) {
    .chapter-pagination {
        grid-template-columns: 1fr;
    }
    .chapter-pagination .page-prev,
    .chapter-pagination .page-next {
        text-align: center;
    }
}