/*
 * 糖心vlog - 原创样式表
 * 设计理念：现代、专业、平易近人
 * 版本：1.0.0
 */

/* ========================================
   1. CSS变量定义
   ======================================== */
:root {
    /* 主色调 */
    --primary-color: #E91E63;
    --primary-dark: #C2185B;
    --primary-light: #F8BBD9;
    
    /* 辅助色 */
    --secondary-color: #673AB7;
    --secondary-dark: #512DA8;
    --secondary-light: #D1C4E9;
    
    /* 点缀色 */
    --accent-color: #FFC107;
    --accent-dark: #FFA000;
    --accent-light: #FFECB3;
    
    /* 背景色 */
    --bg-primary: #F8F9FA;
    --bg-secondary: #FFFFFF;
    --bg-dark: #1A1A2E;
    --bg-gradient: linear-gradient(135deg, #E91E63 0%, #673AB7 100%);
    
    /* 文字色 */
    --text-primary: #212529;
    --text-secondary: #6C757D;
    --text-light: #ADB5BD;
    --text-white: #FFFFFF;
    
    /* 边框与阴影 */
    --border-color: #DEE2E6;
    --border-radius-sm: 8px;
    --border-radius-md: 12px;
    --border-radius-lg: 20px;
    --border-radius-full: 50px;
    --shadow-sm: 0 2px 8px rgba(0, 0, 0, 0.08);
    --shadow-md: 0 4px 16px rgba(0, 0, 0, 0.12);
    --shadow-lg: 0 8px 32px rgba(0, 0, 0, 0.16);
    --shadow-hover: 0 12px 40px rgba(233, 30, 99, 0.2);
    
    /* 间距 */
    --spacing-xs: 0.5rem;
    --spacing-sm: 1rem;
    --spacing-md: 1.5rem;
    --spacing-lg: 2rem;
    --spacing-xl: 3rem;
    --spacing-xxl: 5rem;
    
    /* 过渡 */
    --transition-fast: 0.2s ease;
    --transition-normal: 0.3s ease;
    --transition-slow: 0.5s ease;
    
    /* 容器宽度 */
    --container-max: 1200px;
    --container-narrow: 900px;
}

/* ========================================
   2. 重置与基础样式
   ======================================== */
*, *::before, *::after {
    box-sizing: border-box;
    margin: 0;
    padding: 0;
}

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

body {
    font-family: 'Roboto', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
    font-size: 1rem;
    line-height: 1.7;
    color: var(--text-primary);
    background-color: var(--bg-primary);
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
}

h1, h2, h3, h4, h5, h6 {
    font-family: 'Poppins', sans-serif;
    font-weight: 600;
    line-height: 1.3;
    color: var(--text-primary);
    margin-bottom: var(--spacing-sm);
}

h1 { font-size: 2.5rem; }
h2 { font-size: 2rem; }
h3 { font-size: 1.5rem; }
h4 { font-size: 1.25rem; }
h5 { font-size: 1.1rem; }
h6 { font-size: 1rem; }

p {
    margin-bottom: var(--spacing-sm);
}

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

a:hover {
    color: var(--primary-dark);
}

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

ul, ol {
    list-style: none;
}

/* ========================================
   3. 布局容器
   ======================================== */
.container {
    width: 100%;
    max-width: var(--container-max);
    margin: 0 auto;
    padding: 0 var(--spacing-md);
}

.container-narrow {
    max-width: var(--container-narrow);
}

.section {
    padding: var(--spacing-xxl) 0;
}

.section-alt {
    background-color: var(--bg-secondary);
}

.section-dark {
    background-color: var(--bg-dark);
    color: var(--text-white);
}

.section-gradient {
    background: var(--bg-gradient);
    color: var(--text-white);
}

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

.section-title::after {
    content: '';
    display: block;
    width: 60px;
    height: 4px;
    background: var(--bg-gradient);
    margin: var(--spacing-sm) auto 0;
    border-radius: var(--border-radius-full);
}

.section-subtitle {
    color: var(--text-secondary);
    font-size: 1.1rem;
    max-width: 600px;
    margin: 0 auto;
}

/* ========================================
   4. 导航栏
   ======================================== */
.navbar {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    background: var(--bg-secondary);
    box-shadow: var(--shadow-sm);
    z-index: 1000;
    transition: all var(--transition-normal);
}

.navbar.scrolled {
    box-shadow: var(--shadow-md);
}

.navbar-inner {
    display: flex;
    align-items: center;
    justify-content: space-between;
    height: 70px;
}

.navbar-logo {
    display: flex;
    align-items: center;
    gap: var(--spacing-xs);
    font-family: 'Poppins', sans-serif;
    font-size: 1.5rem;
    font-weight: 700;
    color: var(--primary-color);
}

.navbar-logo img {
    height: 40px;
    width: auto;
}

.navbar-menu {
    display: flex;
    align-items: center;
    gap: var(--spacing-md);
}

.navbar-link {
    font-weight: 500;
    color: var(--text-primary);
    padding: var(--spacing-xs) var(--spacing-sm);
    border-radius: var(--border-radius-sm);
    transition: all var(--transition-fast);
    position: relative;
}

.navbar-link::after {
    content: '';
    position: absolute;
    bottom: 0;
    left: 50%;
    width: 0;
    height: 2px;
    background: var(--primary-color);
    transition: all var(--transition-fast);
    transform: translateX(-50%);
}

.navbar-link:hover::after,
.navbar-link.active::after {
    width: 80%;
}

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

.navbar-cta {
    display: inline-flex;
    align-items: center;
    gap: var(--spacing-xs);
    padding: var(--spacing-xs) var(--spacing-md);
    background: var(--bg-gradient);
    color: var(--text-white);
    font-weight: 600;
    border-radius: var(--border-radius-full);
    transition: all var(--transition-fast);
}

.navbar-cta:hover {
    color: var(--text-white);
    transform: translateY(-2px);
    box-shadow: var(--shadow-hover);
}

.navbar-toggle {
    display: none;
    flex-direction: column;
    gap: 5px;
    cursor: pointer;
    padding: var(--spacing-xs);
}

.navbar-toggle span {
    display: block;
    width: 25px;
    height: 3px;
    background: var(--text-primary);
    border-radius: 2px;
    transition: all var(--transition-fast);
}

/* ========================================
   5. 欢迎区域 / Hero
   ======================================== */
.hero {
    padding: calc(70px + var(--spacing-xxl)) 0 var(--spacing-xxl);
    background: var(--bg-gradient);
    color: var(--text-white);
    text-align: center;
    position: relative;
    overflow: hidden;
}

.hero::before {
    content: '';
    position: absolute;
    top: -50%;
    left: -50%;
    width: 200%;
    height: 200%;
    background: radial-gradient(circle, rgba(255,255,255,0.1) 0%, transparent 70%);
    animation: heroGlow 15s linear infinite;
}

@keyframes heroGlow {
    0% { transform: rotate(0deg); }
    100% { transform: rotate(360deg); }
}

.hero-content {
    position: relative;
    z-index: 1;
}

.hero-title {
    font-size: 3rem;
    margin-bottom: var(--spacing-md);
    color: var(--text-white);
}

.hero-text {
    font-size: 1.15rem;
    max-width: 700px;
    margin: 0 auto var(--spacing-lg);
    opacity: 0.95;
    line-height: 1.8;
}

.hero-buttons {
    display: flex;
    justify-content: center;
    gap: var(--spacing-sm);
    flex-wrap: wrap;
}

/* ========================================
   6. 按钮样式
   ======================================== */
.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: var(--spacing-xs);
    padding: var(--spacing-sm) var(--spacing-lg);
    font-family: 'Poppins', sans-serif;
    font-size: 1rem;
    font-weight: 600;
    border: none;
    border-radius: var(--border-radius-full);
    cursor: pointer;
    transition: all var(--transition-fast);
    text-decoration: none;
}

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

.btn-primary:hover {
    background: var(--primary-light);
    color: var(--primary-dark);
    transform: translateY(-3px);
    box-shadow: var(--shadow-md);
}

.btn-secondary {
    background: transparent;
    color: var(--text-white);
    border: 2px solid var(--text-white);
}

.btn-secondary:hover {
    background: var(--text-white);
    color: var(--primary-color);
    transform: translateY(-3px);
}

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

.btn-accent:hover {
    background: var(--accent-dark);
    transform: translateY(-3px);
    box-shadow: var(--shadow-md);
}

.btn-gradient {
    background: var(--bg-gradient);
    color: var(--text-white);
}

.btn-gradient:hover {
    transform: translateY(-3px);
    box-shadow: var(--shadow-hover);
    color: var(--text-white);
}

/* ========================================
   7. 视频卡片
   ======================================== */
.video-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
    gap: var(--spacing-lg);
}

.video-card {
    background: var(--bg-secondary);
    border-radius: var(--border-radius-md);
    overflow: hidden;
    box-shadow: var(--shadow-sm);
    transition: all var(--transition-normal);
    border: 1px solid var(--border-color);
}

.video-card:hover {
    transform: translateY(-8px);
    box-shadow: var(--shadow-hover);
}

.video-card-thumb {
    position: relative;
    aspect-ratio: 16/9;
    overflow: hidden;
    background: var(--bg-dark);
}

.video-card-thumb img {
    width: 100%;
    height: 100%;
    object-fit: cover;
    transition: transform var(--transition-slow);
}

.video-card:hover .video-card-thumb img {
    transform: scale(1.08);
}

.video-card-play {
    position: absolute;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
    width: 60px;
    height: 60px;
    background: var(--bg-gradient);
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    opacity: 0;
    transition: all var(--transition-fast);
}

.video-card-play::after {
    content: '';
    width: 0;
    height: 0;
    border-left: 18px solid var(--text-white);
    border-top: 12px solid transparent;
    border-bottom: 12px solid transparent;
    margin-left: 4px;
}

.video-card:hover .video-card-play {
    opacity: 1;
}

.video-card-badge {
    position: absolute;
    top: var(--spacing-sm);
    left: var(--spacing-sm);
    padding: 4px 12px;
    background: var(--accent-color);
    color: var(--text-primary);
    font-size: 0.75rem;
    font-weight: 600;
    border-radius: var(--border-radius-full);
}

.video-card-body {
    padding: var(--spacing-md);
}

.video-card-title {
    font-size: 1.1rem;
    margin-bottom: var(--spacing-xs);
    display: -webkit-box;
    -webkit-line-clamp: 2;
    -webkit-box-orient: vertical;
    overflow: hidden;
}

.video-card-meta {
    display: flex;
    align-items: center;
    gap: var(--spacing-sm);
    margin-bottom: var(--spacing-xs);
    font-size: 0.9rem;
}

.video-card-rating {
    color: var(--accent-color);
    font-weight: 600;
}

.video-card-views {
    color: var(--text-secondary);
}

.video-card-desc {
    color: var(--text-secondary);
    font-size: 0.9rem;
    display: -webkit-box;
    -webkit-line-clamp: 2;
    -webkit-box-orient: vertical;
    overflow: hidden;
    margin-bottom: 0;
}

/* ========================================
   8. 精选视频区
   ======================================== */
.featured-video {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: var(--spacing-xl);
    align-items: center;
}

.featured-video-player {
    position: relative;
    aspect-ratio: 16/9;
    border-radius: var(--border-radius-lg);
    overflow: hidden;
    box-shadow: var(--shadow-lg);
}

.featured-video-player img {
    width: 100%;
    height: 100%;
    object-fit: cover;
}

.featured-video-overlay {
    position: absolute;
    inset: 0;
    background: rgba(0,0,0,0.3);
    display: flex;
    align-items: center;
    justify-content: center;
    cursor: pointer;
    transition: background var(--transition-fast);
}

.featured-video-overlay:hover {
    background: rgba(0,0,0,0.5);
}

.featured-play-btn {
    width: 80px;
    height: 80px;
    background: var(--bg-gradient);
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    transition: transform var(--transition-fast);
}

.featured-play-btn::after {
    content: '';
    width: 0;
    height: 0;
    border-left: 24px solid var(--text-white);
    border-top: 16px solid transparent;
    border-bottom: 16px solid transparent;
    margin-left: 6px;
}

.featured-video-overlay:hover .featured-play-btn {
    transform: scale(1.1);
}

.featured-video-info h3 {
    font-size: 1.75rem;
    margin-bottom: var(--spacing-md);
}

.featured-video-info p {
    color: var(--text-secondary);
    font-size: 1.05rem;
    line-height: 1.8;
}

/* ========================================
   9. 关于我们
   ======================================== */
.about-content {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: var(--spacing-xl);
    align-items: center;
}

.about-image {
    position: relative;
}

.about-image-main {
    border-radius: var(--border-radius-lg);
    box-shadow: var(--shadow-lg);
}

.about-image-badge {
    position: absolute;
    bottom: -20px;
    right: -20px;
    background: var(--bg-gradient);
    color: var(--text-white);
    padding: var(--spacing-md) var(--spacing-lg);
    border-radius: var(--border-radius-md);
    text-align: center;
    box-shadow: var(--shadow-md);
}

.about-image-badge .number {
    font-family: 'Poppins', sans-serif;
    font-size: 2.5rem;
    font-weight: 700;
    line-height: 1;
}

.about-image-badge .label {
    font-size: 0.9rem;
    opacity: 0.9;
}

.about-text h2 {
    margin-bottom: var(--spacing-md);
}

.about-text p {
    color: var(--text-secondary);
    margin-bottom: var(--spacing-md);
}

.about-features {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: var(--spacing-sm);
    margin-top: var(--spacing-lg);
}

.about-feature {
    display: flex;
    align-items: center;
    gap: var(--spacing-xs);
}

.about-feature-icon {
    width: 24px;
    height: 24px;
    background: var(--primary-light);
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    color: var(--primary-color);
    font-size: 0.8rem;
}

/* ========================================
   10. 资质认证
   ======================================== */
.credentials-grid {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    gap: var(--spacing-lg);
}

.credential-card {
    text-align: center;
    padding: var(--spacing-lg);
    background: var(--bg-secondary);
    border-radius: var(--border-radius-md);
    box-shadow: var(--shadow-sm);
    transition: all var(--transition-normal);
}

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

.credential-icon {
    width: 70px;
    height: 70px;
    margin: 0 auto var(--spacing-md);
    background: var(--bg-gradient);
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 1.75rem;
    color: var(--text-white);
}

.credential-card h4 {
    margin-bottom: var(--spacing-xs);
}

.credential-card p {
    color: var(--text-secondary);
    font-size: 0.9rem;
    margin-bottom: 0;
}

/* ========================================
   11. 支付方式
   ======================================== */
.payment-methods {
    display: flex;
    justify-content: center;
    flex-wrap: wrap;
    gap: var(--spacing-lg);
}

.payment-item {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: var(--spacing-xs);
    padding: var(--spacing-md) var(--spacing-lg);
    background: var(--bg-secondary);
    border-radius: var(--border-radius-md);
    box-shadow: var(--shadow-sm);
    transition: all var(--transition-fast);
    min-width: 120px;
}

.payment-item:hover {
    transform: translateY(-3px);
    box-shadow: var(--shadow-md);
}

.payment-icon {
    font-size: 2.5rem;
}

.payment-name {
    font-weight: 500;
    color: var(--text-secondary);
    font-size: 0.9rem;
}

/* ========================================
   12. 客户支持
   ======================================== */
.support-grid {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: var(--spacing-lg);
}

.support-card {
    text-align: center;
    padding: var(--spacing-xl);
    background: var(--bg-secondary);
    border-radius: var(--border-radius-md);
    box-shadow: var(--shadow-sm);
    transition: all var(--transition-normal);
}

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

.support-icon {
    width: 60px;
    height: 60px;
    margin: 0 auto var(--spacing-md);
    background: var(--primary-light);
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 1.5rem;
    color: var(--primary-color);
}

.support-card h4 {
    margin-bottom: var(--spacing-xs);
}

.support-card p {
    color: var(--text-secondary);
    margin-bottom: 0;
}

/* ========================================
   13. 负责任观影
   ======================================== */
.responsible-content {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: var(--spacing-lg);
}

.responsible-item {
    padding: var(--spacing-lg);
    background: var(--bg-secondary);
    border-radius: var(--border-radius-md);
    border-left: 4px solid var(--primary-color);
}

.responsible-item h4 {
    color: var(--primary-color);
    margin-bottom: var(--spacing-xs);
}

.responsible-item p {
    color: var(--text-secondary);
    margin-bottom: 0;
    font-size: 0.95rem;
}

/* ========================================
   14. FAQ手风琴
   ======================================== */
.faq-list {
    max-width: 800px;
    margin: 0 auto;
}

.faq-item {
    background: var(--bg-secondary);
    border-radius: var(--border-radius-md);
    margin-bottom: var(--spacing-sm);
    overflow: hidden;
    box-shadow: var(--shadow-sm);
}

.faq-question {
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: var(--spacing-md) var(--spacing-lg);
    cursor: pointer;
    transition: background var(--transition-fast);
}

.faq-question:hover {
    background: var(--bg-primary);
}

.faq-question h4 {
    margin-bottom: 0;
    font-size: 1rem;
    font-weight: 500;
}

.faq-icon {
    width: 30px;
    height: 30px;
    background: var(--primary-light);
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    color: var(--primary-color);
    font-size: 1.25rem;
    transition: transform var(--transition-fast);
    flex-shrink: 0;
}

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

.faq-answer {
    max-height: 0;
    overflow: hidden;
    transition: max-height var(--transition-normal), padding var(--transition-normal);
    background: var(--bg-primary);
    border-top: 1px solid var(--border-color);
}

.faq-answer-inner {
    padding: var(--spacing-md) var(--spacing-lg);
    color: var(--text-secondary);
    line-height: 1.8;
}

.faq-item.active .faq-answer {
    max-height: 500px;
}

.faq-item.active {
    box-shadow: var(--shadow-md);
    border-left: 3px solid var(--primary-color);
}

/* ========================================
   15. 用户评价
   ======================================== */
.reviews-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(350px, 1fr));
    gap: var(--spacing-lg);
}

.review-card {
    background: var(--bg-secondary);
    border-radius: var(--border-radius-md);
    padding: var(--spacing-lg);
    box-shadow: var(--shadow-sm);
    transition: all var(--transition-normal);
}

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

.review-header {
    display: flex;
    align-items: center;
    gap: var(--spacing-sm);
    margin-bottom: var(--spacing-md);
}

.review-avatar {
    width: 50px;
    height: 50px;
    background: var(--bg-gradient);
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    color: var(--text-white);
    font-weight: 600;
    font-size: 1.25rem;
}

.review-info h5 {
    margin-bottom: 2px;
    font-size: 1rem;
}

.review-location {
    color: var(--text-secondary);
    font-size: 0.85rem;
}

.review-rating {
    color: var(--accent-color);
    font-size: 0.9rem;
    margin-bottom: var(--spacing-sm);
}

.review-content {
    color: var(--text-secondary);
    font-size: 0.95rem;
    line-height: 1.7;
    margin-bottom: var(--spacing-sm);
}

.review-date {
    color: var(--text-light);
    font-size: 0.8rem;
}

/* ========================================
   16. 热门标签
   ======================================== */
.tags-cloud {
    display: flex;
    flex-wrap: wrap;
    justify-content: center;
    gap: var(--spacing-sm);
}

.tag {
    display: inline-block;
    padding: var(--spacing-xs) var(--spacing-md);
    background: var(--bg-secondary);
    color: var(--text-primary);
    border-radius: var(--border-radius-full);
    font-size: 0.9rem;
    transition: all var(--transition-fast);
    border: 1px solid var(--border-color);
}

.tag:hover {
    background: var(--bg-gradient);
    color: var(--text-white);
    border-color: transparent;
    transform: translateY(-2px);
}

/* ========================================
   17. 页脚
   ======================================== */
.footer {
    background: var(--bg-dark);
    color: var(--text-white);
    padding: var(--spacing-xxl) 0 var(--spacing-lg);
}

.footer-grid {
    display: grid;
    grid-template-columns: 2fr 1fr 1fr 1fr;
    gap: var(--spacing-xl);
    margin-bottom: var(--spacing-xl);
}

.footer-brand {
    max-width: 300px;
}

.footer-logo {
    display: flex;
    align-items: center;
    gap: var(--spacing-xs);
    font-family: 'Poppins', sans-serif;
    font-size: 1.5rem;
    font-weight: 700;
    color: var(--text-white);
    margin-bottom: var(--spacing-md);
}

.footer-brand p {
    color: rgba(255,255,255,0.7);
    font-size: 0.95rem;
    line-height: 1.7;
}

.footer-title {
    font-size: 1.1rem;
    margin-bottom: var(--spacing-md);
    color: var(--text-white);
}

.footer-links {
    display: flex;
    flex-direction: column;
    gap: var(--spacing-xs);
}

.footer-link {
    color: rgba(255,255,255,0.7);
    transition: all var(--transition-fast);
}

.footer-link:hover {
    color: var(--primary-color);
    padding-left: 5px;
}

.footer-bottom {
    border-top: 1px solid rgba(255,255,255,0.1);
    padding-top: var(--spacing-lg);
    display: flex;
    justify-content: space-between;
    align-items: center;
    flex-wrap: wrap;
    gap: var(--spacing-sm);
}

.footer-copyright {
    color: rgba(255,255,255,0.6);
    font-size: 0.9rem;
}

.footer-legal {
    display: flex;
    gap: var(--spacing-md);
}

.footer-legal a {
    color: rgba(255,255,255,0.6);
    font-size: 0.9rem;
}

.footer-legal a:hover {
    color: var(--primary-color);
}

/* ========================================
   18. 面包屑导航
   ======================================== */
.breadcrumb {
    padding: var(--spacing-md) 0;
    margin-top: 70px;
}

.breadcrumb-list {
    display: flex;
    align-items: center;
    gap: var(--spacing-xs);
    font-size: 0.9rem;
}

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

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

.breadcrumb-item a:hover {
    color: var(--primary-color);
}

.breadcrumb-separator {
    color: var(--text-light);
}

.breadcrumb-current {
    color: var(--primary-color);
    font-weight: 500;
}

/* ========================================
   19. 分类页头部
   ======================================== */
.category-header {
    background: var(--bg-gradient);
    color: var(--text-white);
    padding: var(--spacing-xl) 0;
    text-align: center;
}

.category-header h1 {
    color: var(--text-white);
    margin-bottom: var(--spacing-xs);
}

.category-subtitle {
    opacity: 0.9;
    font-size: 1.1rem;
}

/* ========================================
   20. 文章内容
   ======================================== */
.article-content {
    padding: var(--spacing-xl) 0;
}

.article-content h2 {
    margin-top: var(--spacing-xl);
    margin-bottom: var(--spacing-md);
    padding-bottom: var(--spacing-xs);
    border-bottom: 2px solid var(--primary-light);
}

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

.article-content p {
    margin-bottom: var(--spacing-md);
    text-align: justify;
}

.article-content img {
    border-radius: var(--border-radius-md);
    margin: var(--spacing-lg) 0;
    box-shadow: var(--shadow-md);
}

.article-content a {
    color: var(--primary-color);
    text-decoration: underline;
}

/* ========================================
   21. 返回顶部按钮
   ======================================== */
.back-to-top {
    position: fixed;
    bottom: 30px;
    right: 30px;
    width: 50px;
    height: 50px;
    background: var(--bg-gradient);
    color: var(--text-white);
    border: none;
    border-radius: 50%;
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 1.25rem;
    box-shadow: var(--shadow-md);
    opacity: 0;
    visibility: hidden;
    transition: all var(--transition-fast);
    z-index: 999;
}

.back-to-top.visible {
    opacity: 1;
    visibility: visible;
}

.back-to-top:hover {
    transform: translateY(-5px);
    box-shadow: var(--shadow-hover);
}

/* ========================================
   22. 响应式设计
   ======================================== */
@media (max-width: 1200px) {
    .footer-grid {
        grid-template-columns: 1fr 1fr 1fr;
    }
    
    .footer-brand {
        grid-column: 1 / -1;
        max-width: 100%;
        text-align: center;
        margin-bottom: var(--spacing-md);
    }
}

@media (max-width: 992px) {
    .featured-video,
    .about-content {
        grid-template-columns: 1fr;
        gap: var(--spacing-lg);
    }
    
    .about-image {
        order: -1;
    }
    
    .credentials-grid {
        grid-template-columns: repeat(2, 1fr);
    }
    
    .support-grid,
    .responsible-content {
        grid-template-columns: 1fr;
    }
}

@media (max-width: 768px) {
    html {
        font-size: 15px;
    }
    
    .navbar-menu {
        position: fixed;
        top: 70px;
        left: 0;
        right: 0;
        background: var(--bg-secondary);
        flex-direction: column;
        padding: var(--spacing-lg);
        gap: var(--spacing-sm);
        box-shadow: var(--shadow-md);
        transform: translateY(-100%);
        opacity: 0;
        visibility: hidden;
        transition: all var(--transition-normal);
    }
    
    .navbar-menu.active {
        transform: translateY(0);
        opacity: 1;
        visibility: visible;
    }
    
    .navbar-toggle {
        display: flex;
    }
    
    .navbar-toggle.active span:nth-child(1) {
        transform: rotate(45deg) translate(5px, 5px);
    }
    
    .navbar-toggle.active span:nth-child(2) {
        opacity: 0;
    }
    
    .navbar-toggle.active span:nth-child(3) {
        transform: rotate(-45deg) translate(6px, -6px);
    }
    
    .hero-title {
        font-size: 2rem;
    }
    
    .section {
        padding: var(--spacing-xl) 0;
    }
    
    .section-title {
        font-size: 1.75rem;
    }
    
    .video-grid {
        grid-template-columns: 1fr;
    }
    
    .credentials-grid {
        grid-template-columns: 1fr;
    }
    
    .footer-grid {
        grid-template-columns: 1fr;
        text-align: center;
    }
    
    .footer-bottom {
        flex-direction: column;
        text-align: center;
    }
    
    .reviews-grid {
        grid-template-columns: 1fr;
    }
    
    .payment-methods {
        gap: var(--spacing-sm);
    }
    
    .payment-item {
        min-width: 100px;
        padding: var(--spacing-sm);
    }
}

@media (max-width: 480px) {
    .container {
        padding: 0 var(--spacing-sm);
    }
    
    .hero-buttons {
        flex-direction: column;
    }
    
    .btn {
        width: 100%;
    }
    
    .about-features {
        grid-template-columns: 1fr;
    }
}

/* ========================================
   23. 工具类
   ======================================== */
.text-center { text-align: center; }
.text-left { text-align: left; }
.text-right { text-align: right; }

.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); }

.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); }

.hidden { display: none; }
.visible { display: block; }

/* ========================================
   24. 动画
   ======================================== */
@keyframes fadeIn {
    from { opacity: 0; transform: translateY(20px); }
    to { opacity: 1; transform: translateY(0); }
}

@keyframes slideInLeft {
    from { opacity: 0; transform: translateX(-30px); }
    to { opacity: 1; transform: translateX(0); }
}

@keyframes slideInRight {
    from { opacity: 0; transform: translateX(30px); }
    to { opacity: 1; transform: translateX(0); }
}

@keyframes pulse {
    0%, 100% { transform: scale(1); }
    50% { transform: scale(1.05); }
}

.animate-fadeIn {
    animation: fadeIn 0.6s ease forwards;
}

.animate-slideInLeft {
    animation: slideInLeft 0.6s ease forwards;
}

.animate-slideInRight {
    animation: slideInRight 0.6s ease forwards;
}