/*
 * 51视频 - 原创主题样式
 * 域名：mjizdkd.cn
 * 设计系统：深色科技风 + 橙红品牌色
 */

/* ============================================================
   1. CSS变量 / 设计令牌
   ============================================================ */
:root {
  /* 品牌色 - 橙红渐变系 */
  --brand-primary:   #ff5722;
  --brand-secondary: #ff8a50;
  --brand-accent:    #e64a19;
  --brand-gradient:  linear-gradient(135deg, #ff5722 0%, #ff8a50 50%, #ffd740 100%);

  /* 背景色系 */
  --bg-main:   #0d1117;
  --bg-card:   #161b27;
  --bg-hover:  #1e2535;
  --bg-input:  #1a2030;

  /* 文字色系 */
  --text-primary:   #f0f2f8;
  --text-secondary: #8892a4;
  --text-muted:     #4a5568;
  --text-accent:    #ff5722;

  /* 边框 */
  --border-color:  rgba(255,255,255,0.08);
  --border-hover:  rgba(255,87,34,0.4);

  /* 圆角 */
  --radius-sm: 8px;
  --radius-md: 12px;
  --radius-lg: 20px;
  --radius-xl: 28px;

  /* 阴影 */
  --shadow-sm:  0 2px 8px rgba(0,0,0,0.3);
  --shadow-md:  0 8px 24px rgba(0,0,0,0.4);
  --shadow-lg:  0 16px 48px rgba(0,0,0,0.5);
  --shadow-brand: 0 8px 32px rgba(255,87,34,0.3);

  /* 过渡 */
  --transition: all 0.25s cubic-bezier(0.4,0,0.2,1);

  /* 字体 */
  --font-main: 'PingFang SC','Microsoft YaHei','Hiragino Sans GB',sans-serif;
}

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

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

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

a { color: inherit; text-decoration: none; transition: var(--transition); }
a:hover { color: var(--brand-primary); }
img { max-width: 100%; height: auto; display: block; }
ul, ol { list-style: none; }
button { cursor: pointer; font-family: var(--font-main); }
input, select, textarea { font-family: var(--font-main); }

/* ============================================================
   3. 布局工具
   ============================================================ */
.container {
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 20px;
}

.section      { padding: 80px 0; }
.section-sm   { padding: 48px 0; }

.text-center  { text-align: center; }
.text-gradient {
  background: var(--brand-gradient);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

/* ============================================================
   4. 导航头部
   ============================================================ */
.site-header {
  position: sticky;
  top: 0;
  z-index: 200;
  background: rgba(13,17,23,0.95);
  backdrop-filter: blur(16px);
  -webkit-backdrop-filter: blur(16px);
  border-bottom: 1px solid var(--border-color);
  height: 64px;
  display: flex;
  align-items: center;
}

.header-inner {
  display: flex;
  align-items: center;
  gap: 24px;
  height: 100%;
}

/* Logo */
.site-logo {
  display: flex;
  align-items: center;
  gap: 10px;
  flex-shrink: 0;
}
.site-logo img {
  width: 36px;
  height: 36px;
  border-radius: 8px;
  object-fit: cover;
}
.logo-text {
  font-size: 1.2rem;
  font-weight: 800;
  background: var(--brand-gradient);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
  white-space: nowrap;
}

/* 主导航 */
.main-nav {
  display: flex;
  align-items: center;
  gap: 4px;
  flex: 1;
}
.main-nav a {
  padding: 6px 14px;
  border-radius: var(--radius-sm);
  font-size: 14px;
  font-weight: 500;
  color: var(--text-secondary);
  transition: var(--transition);
  white-space: nowrap;
}
.main-nav a:hover,
.main-nav a.active {
  color: var(--text-primary);
  background: var(--bg-hover);
}
.main-nav a.active {
  color: var(--brand-primary);
}

/* 搜索框 */
.header-search {
  position: relative;
  flex: 1;
  max-width: 320px;
}
.header-search input {
  width: 100%;
  padding: 8px 16px 8px 36px;
  background: var(--bg-card);
  border: 1px solid var(--border-color);
  border-radius: 20px;
  color: var(--text-primary);
  font-size: 13px;
  outline: none;
  transition: var(--transition);
}
.header-search input:focus {
  border-color: var(--brand-primary);
  box-shadow: 0 0 0 3px rgba(255,87,34,0.15);
}
.search-icon {
  position: absolute;
  left: 12px;
  top: 50%;
  transform: translateY(-50%);
  font-size: 14px;
  pointer-events: none;
}
.search-dropdown {
  display: none;
  position: absolute;
  top: calc(100% + 8px);
  left: 0;
  right: 0;
  background: var(--bg-card);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-md);
  box-shadow: var(--shadow-lg);
  z-index: 100;
  overflow: hidden;
}
.search-dropdown.show { display: block; }
.search-dropdown li {
  padding: 10px 16px;
  font-size: 13px;
  color: var(--text-secondary);
  cursor: pointer;
  transition: var(--transition);
}
.search-dropdown li:hover {
  background: var(--bg-hover);
  color: var(--text-primary);
}

/* 右侧操作 */
.header-actions {
  display: flex;
  align-items: center;
  gap: 12px;
  flex-shrink: 0;
}
.btn-join {
  padding: 7px 18px;
  background: var(--brand-primary);
  color: #fff !important;
  border-radius: 20px;
  font-size: 13px;
  font-weight: 600;
  transition: var(--transition);
  white-space: nowrap;
}
.btn-join:hover {
  background: var(--brand-accent);
  transform: translateY(-1px);
  box-shadow: var(--shadow-brand);
}

/* 汉堡菜单 */
.hamburger {
  display: none;
  flex-direction: column;
  gap: 5px;
  background: none;
  border: none;
  padding: 4px;
}
.hamburger span {
  display: block;
  width: 22px;
  height: 2px;
  background: var(--text-primary);
  border-radius: 2px;
  transition: var(--transition);
}

/* ============================================================
   5. 按钮系统
   ============================================================ */
.btn {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 10px 24px;
  border-radius: var(--radius-sm);
  font-size: 14px;
  font-weight: 600;
  border: none;
  transition: var(--transition);
  cursor: pointer;
  white-space: nowrap;
}
.btn-lg { padding: 14px 32px; font-size: 15px; }
.btn-sm { padding: 7px 16px; font-size: 13px; }

.btn-primary {
  background: var(--brand-primary);
  color: #fff;
}
.btn-primary:hover {
  background: var(--brand-accent);
  transform: translateY(-2px);
  box-shadow: var(--shadow-brand);
  color: #fff;
}

.btn-secondary {
  background: var(--bg-card);
  color: var(--text-primary);
  border: 1px solid var(--border-color);
}
.btn-secondary:hover {
  background: var(--bg-hover);
  border-color: var(--brand-primary);
  color: var(--brand-primary);
  transform: translateY(-2px);
}

.btn-accent {
  background: var(--brand-gradient);
  color: #fff;
}
.btn-accent:hover {
  opacity: 0.9;
  transform: translateY(-2px);
  box-shadow: var(--shadow-brand);
  color: #fff;
}

/* ============================================================
   6. 徽章
   ============================================================ */
.badge {
  display: inline-block;
  padding: 3px 10px;
  border-radius: 12px;
  font-size: 11px;
  font-weight: 700;
  letter-spacing: 0.5px;
}
.badge-hot  { background: rgba(255,87,34,0.2); color: #ff5722; border: 1px solid rgba(255,87,34,0.3); }
.badge-new  { background: rgba(76,175,80,0.2);  color: #4caf50; border: 1px solid rgba(76,175,80,0.3); }
.badge-ai   { background: rgba(103,58,183,0.2); color: #9c27b0; border: 1px solid rgba(103,58,183,0.3); }

/* ============================================================
   7. 英雄区
   ============================================================ */
.hero-section {
  position: relative;
  min-height: 600px;
  display: flex;
  align-items: center;
  overflow: hidden;
  padding: 80px 0;
}
.hero-bg {
  position: absolute;
  inset: 0;
  background: radial-gradient(ellipse at 60% 50%, rgba(255,87,34,0.12) 0%, transparent 60%),
              radial-gradient(ellipse at 20% 80%, rgba(103,58,183,0.08) 0%, transparent 50%),
              var(--bg-main);
}
.hero-bg::before {
  content: '';
  position: absolute;
  inset: 0;
  background-image:
    radial-gradient(circle at 1px 1px, rgba(255,255,255,0.04) 1px, transparent 0);
  background-size: 40px 40px;
}
.hero-content {
  position: relative;
  z-index: 1;
  max-width: 680px;
}
.hero-tag {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 6px 16px;
  background: rgba(255,87,34,0.12);
  border: 1px solid rgba(255,87,34,0.25);
  border-radius: 20px;
  font-size: 13px;
  color: var(--brand-secondary);
  margin-bottom: 24px;
}
.hero-tag .dot {
  width: 6px;
  height: 6px;
  background: var(--brand-primary);
  border-radius: 50%;
  animation: pulse 1.5s infinite;
}
@keyframes pulse {
  0%, 100% { opacity: 1; transform: scale(1); }
  50%       { opacity: 0.5; transform: scale(0.8); }
}

.hero-content h1 {
  font-size: clamp(2.4rem, 5vw, 3.8rem);
  font-weight: 900;
  line-height: 1.15;
  margin-bottom: 20px;
  letter-spacing: -0.5px;
}
.hero-content h1 span {
  background: var(--brand-gradient);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}
.hero-content p {
  font-size: 1.1rem;
  color: var(--text-secondary);
  margin-bottom: 32px;
  line-height: 1.8;
}
.hero-btns {
  display: flex;
  gap: 16px;
  flex-wrap: wrap;
  margin-bottom: 48px;
}
.hero-stats {
  display: flex;
  gap: 32px;
  flex-wrap: wrap;
}
.hero-stat-item .num {
  font-size: 1.8rem;
  font-weight: 800;
  background: var(--brand-gradient);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}
.hero-stat-item .label {
  font-size: 12px;
  color: var(--text-muted);
  margin-top: 2px;
}

/* ============================================================
   8. 区块标题
   ============================================================ */
.section-header {
  margin-bottom: 48px;
}
.section-header h2 {
  font-size: clamp(1.6rem, 3vw, 2.2rem);
  font-weight: 800;
  margin-bottom: 12px;
  letter-spacing: -0.3px;
}
.section-header p {
  color: var(--text-secondary);
  font-size: 1rem;
  max-width: 600px;
}
.section-header.text-center p { margin: 0 auto; }

.section-divider {
  width: 48px;
  height: 4px;
  background: var(--brand-gradient);
  border-radius: 2px;
  margin-bottom: 16px;
}
.section-header.text-center .section-divider { margin: 0 auto 16px; }

/* ============================================================
   9. 视频卡片
   ============================================================ */
.video-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
  gap: 20px;
}

.video-card {
  background: var(--bg-card);
  border-radius: var(--radius-md);
  overflow: hidden;
  border: 1px solid var(--border-color);
  transition: var(--transition);
  cursor: pointer;
}
.video-card:hover {
  transform: translateY(-4px);
  border-color: var(--border-hover);
  box-shadow: var(--shadow-md);
}
.video-card.animate-in { animation: fadeInUp 0.5s ease forwards; }

.video-thumb {
  position: relative;
  aspect-ratio: 16/9;
  overflow: hidden;
  background: var(--bg-hover);
}
.video-thumb img {
  width: 100%;
  height: 100%;
  object-fit: cover;
  transition: transform 0.4s ease;
}
.video-card:hover .video-thumb img { transform: scale(1.05); }

.video-play-btn {
  position: absolute;
  inset: 0;
  display: flex;
  align-items: center;
  justify-content: center;
  background: rgba(0,0,0,0);
  transition: var(--transition);
}
.video-card:hover .video-play-btn { background: rgba(0,0,0,0.45); }

.play-circle {
  width: 52px;
  height: 52px;
  background: rgba(255,87,34,0.9);
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  opacity: 0;
  transform: scale(0.7);
  transition: var(--transition);
  box-shadow: 0 0 30px rgba(255,87,34,0.5);
}
.play-circle svg {
  width: 22px;
  height: 22px;
  fill: white;
  margin-left: 3px;
}
.video-card:hover .play-circle {
  opacity: 1;
  transform: scale(1);
}

.video-duration {
  position: absolute;
  bottom: 8px;
  right: 8px;
  background: rgba(0,0,0,0.75);
  color: #fff;
  font-size: 11px;
  font-weight: 600;
  padding: 2px 7px;
  border-radius: 4px;
}
.video-tag-badge {
  position: absolute;
  top: 8px;
  left: 8px;
}

.video-info { padding: 14px 16px; }
.video-title {
  font-size: 14px;
  font-weight: 600;
  line-height: 1.5;
  margin-bottom: 10px;
  display: -webkit-box;
  -webkit-line-clamp: 2;
  -webkit-box-orient: vertical;
  overflow: hidden;
}
.video-meta {
  display: flex;
  gap: 12px;
  font-size: 12px;
  color: var(--text-muted);
  flex-wrap: wrap;
}
.video-meta .icon { margin-right: 3px; }

/* ============================================================
   10. 功能卡片
   ============================================================ */
.feature-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
  gap: 20px;
}

.feature-card {
  background: var(--bg-main);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-md);
  padding: 28px 24px;
  transition: var(--transition);
}
.feature-card:hover {
  border-color: var(--border-hover);
  transform: translateY(-3px);
  box-shadow: var(--shadow-md);
}
.feature-card.animate-in { animation: fadeInUp 0.5s ease forwards; }

.feature-icon {
  width: 52px;
  height: 52px;
  border-radius: var(--radius-sm);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 22px;
  margin-bottom: 16px;
}
.feature-icon.orange { background: rgba(255,87,34,0.15); }
.feature-icon.purple { background: rgba(103,58,183,0.15); }
.feature-icon.gold   { background: rgba(255,215,64,0.15); }
.feature-icon.blue   { background: rgba(33,150,243,0.15); }

.feature-card h3 {
  font-size: 1rem;
  font-weight: 700;
  margin-bottom: 10px;
}
.feature-card p {
  font-size: 14px;
  color: var(--text-secondary);
  line-height: 1.7;
}

/* ============================================================
   11. 专家卡片
   ============================================================ */
.expert-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(260px, 1fr));
  gap: 20px;
}

.expert-card {
  background: var(--bg-card);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-lg);
  overflow: hidden;
  transition: var(--transition);
}
.expert-card:hover {
  border-color: var(--border-hover);
  transform: translateY(-4px);
  box-shadow: var(--shadow-md);
}
.expert-card.animate-in { animation: fadeInUp 0.5s ease forwards; }

.expert-photo {
  position: relative;
  aspect-ratio: 4/3;
  overflow: hidden;
}
.expert-photo img {
  width: 100%;
  height: 100%;
  object-fit: cover;
}
.expert-badge {
  position: absolute;
  bottom: 12px;
  left: 12px;
  background: var(--brand-primary);
  color: #fff;
  font-size: 11px;
  font-weight: 700;
  padding: 3px 10px;
  border-radius: 10px;
}

.expert-body { padding: 20px; }
.expert-name {
  font-size: 1.1rem;
  font-weight: 800;
  margin-bottom: 4px;
}
.expert-title {
  font-size: 12px;
  color: var(--brand-primary);
  margin-bottom: 10px;
}
.expert-desc {
  font-size: 13px;
  color: var(--text-secondary);
  line-height: 1.7;
  margin-bottom: 14px;
}
.expert-awards {
  display: flex;
  flex-wrap: wrap;
  gap: 6px;
  margin-bottom: 14px;
}
.expert-awards span {
  background: var(--bg-hover);
  border: 1px solid var(--border-color);
  color: var(--text-secondary);
  font-size: 11px;
  padding: 2px 8px;
  border-radius: 10px;
}
.expert-actions {
  display: flex;
  gap: 8px;
}
.btn-contact, .btn-works {
  flex: 1;
  text-align: center;
  padding: 7px 12px;
  border-radius: var(--radius-sm);
  font-size: 12px;
  font-weight: 600;
  transition: var(--transition);
}
.btn-contact {
  background: var(--brand-primary);
  color: #fff;
}
.btn-contact:hover { background: var(--brand-accent); color: #fff; }
.btn-works {
  background: var(--bg-hover);
  color: var(--text-secondary);
  border: 1px solid var(--border-color);
}
.btn-works:hover { border-color: var(--brand-primary); color: var(--brand-primary); }

/* ============================================================
   12. 评价卡片
   ============================================================ */
.review-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(300px, 1fr));
  gap: 20px;
}

.review-card {
  background: var(--bg-card);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-md);
  padding: 24px;
  transition: var(--transition);
}
.review-card:hover {
  border-color: var(--border-hover);
  transform: translateY(-2px);
}
.review-card.animate-in { animation: fadeInUp 0.5s ease forwards; }

.review-stars {
  color: #ffd740;
  font-size: 16px;
  letter-spacing: 2px;
  margin-bottom: 12px;
}
.review-text {
  font-size: 14px;
  color: var(--text-secondary);
  line-height: 1.8;
  margin-bottom: 16px;
  font-style: italic;
}
.review-user {
  display: flex;
  align-items: center;
  gap: 12px;
}
.review-avatar {
  width: 40px;
  height: 40px;
  border-radius: 50%;
  background: var(--brand-gradient);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 16px;
  font-weight: 800;
  color: #fff;
  flex-shrink: 0;
}
.review-name {
  font-size: 14px;
  font-weight: 700;
}
.review-date {
  font-size: 12px;
  color: var(--text-muted);
}

/* ============================================================
   13. FAQ
   ============================================================ */
.faq-list {
  max-width: 800px;
  margin: 0 auto;
  display: flex;
  flex-direction: column;
  gap: 12px;
}

.faq-item {
  background: var(--bg-main);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-md);
  overflow: hidden;
  transition: var(--transition);
}
.faq-item:hover { border-color: var(--border-hover); }
.faq-item.open  { border-color: var(--brand-primary); }
.faq-item.animate-in { animation: fadeInUp 0.4s ease forwards; }

.faq-question {
  padding: 18px 20px;
  font-size: 15px;
  font-weight: 600;
  cursor: pointer;
  display: flex;
  justify-content: space-between;
  align-items: center;
  gap: 12px;
  user-select: none;
}
.faq-question:hover { color: var(--brand-primary); }
.faq-item.open .faq-question { color: var(--brand-primary); }

.faq-icon {
  font-size: 20px;
  font-weight: 300;
  color: var(--text-muted);
  flex-shrink: 0;
  transition: var(--transition);
}
.faq-item.open .faq-icon { transform: rotate(45deg); color: var(--brand-primary); }

.faq-answer {
  max-height: 0;
  overflow: hidden;
  transition: max-height 0.35s ease;
}
.faq-item.open .faq-answer { max-height: 400px; }
.faq-answer p {
  padding: 0 20px 18px;
  font-size: 14px;
  color: var(--text-secondary);
  line-height: 1.8;
}

/* ============================================================
   14. How-To 步骤
   ============================================================ */
.howto-steps {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(220px, 1fr));
  gap: 20px;
}

.howto-step {
  text-align: center;
  padding: 28px 20px;
  background: var(--bg-main);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-md);
  transition: var(--transition);
}
.howto-step:hover {
  border-color: var(--border-hover);
  transform: translateY(-3px);
}
.howto-step.animate-in { animation: fadeInUp 0.5s ease forwards; }

.step-num {
  width: 48px;
  height: 48px;
  border-radius: 50%;
  background: var(--brand-gradient);
  color: #fff;
  font-size: 1.2rem;
  font-weight: 800;
  display: flex;
  align-items: center;
  justify-content: center;
  margin: 0 auto 16px;
}
.howto-step h4 {
  font-size: 15px;
  font-weight: 700;
  margin-bottom: 8px;
}
.howto-step p {
  font-size: 13px;
  color: var(--text-secondary);
  line-height: 1.7;
}

/* ============================================================
   15. 统计数字
   ============================================================ */
.stats-row {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(160px, 1fr));
  gap: 16px;
}

.stat-box {
  text-align: center;
  padding: 24px 16px;
  background: var(--bg-main);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-md);
}
.stat-box .num {
  font-size: 2rem;
  font-weight: 900;
  background: var(--brand-gradient);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
  line-height: 1;
  margin-bottom: 6px;
}
.stat-box .label {
  font-size: 13px;
  color: var(--text-secondary);
}

/* ============================================================
   16. 合作伙伴
   ============================================================ */
.partner-wall {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
  justify-content: center;
}
.partner-item {
  padding: 10px 24px;
  background: var(--bg-main);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-sm);
  font-size: 14px;
  color: var(--text-secondary);
  transition: var(--transition);
}
.partner-item:hover {
  border-color: var(--brand-primary);
  color: var(--brand-primary);
}

/* ============================================================
   17. 社区功能入口
   ============================================================ */
.community-entries {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(160px, 1fr));
  gap: 16px;
}
.community-entry {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 10px;
  padding: 24px 16px;
  background: var(--bg-card);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-md);
  text-align: center;
  transition: var(--transition);
}
.community-entry:hover {
  border-color: var(--border-hover);
  transform: translateY(-3px);
  box-shadow: var(--shadow-sm);
  color: var(--brand-primary);
}
.entry-icon { font-size: 28px; }
.community-entry h4 { font-size: 14px; font-weight: 700; }
.community-entry p  { font-size: 12px; color: var(--text-muted); }

/* ============================================================
   18. AI卡片
   ============================================================ */
.ai-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(300px, 1fr));
  gap: 20px;
}
.ai-card {
  background: var(--bg-main);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-md);
  padding: 28px 24px;
  transition: var(--transition);
}
.ai-card:hover {
  border-color: rgba(103,58,183,0.4);
  transform: translateY(-3px);
  box-shadow: 0 8px 24px rgba(103,58,183,0.15);
}
.ai-card h3 {
  font-size: 1rem;
  font-weight: 700;
  margin-bottom: 12px;
}
.ai-card p {
  font-size: 14px;
  color: var(--text-secondary);
  line-height: 1.7;
  margin-bottom: 16px;
}
.ai-features {
  display: flex;
  flex-wrap: wrap;
  gap: 6px;
}
.ai-feature-tag {
  background: rgba(103,58,183,0.15);
  color: #9c27b0;
  border: 1px solid rgba(103,58,183,0.25);
  font-size: 11px;
  padding: 3px 9px;
  border-radius: 10px;
}

/* ============================================================
   19. 标签列表
   ============================================================ */
.tag-list {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
}
.tag {
  padding: 6px 16px;
  background: var(--bg-card);
  border: 1px solid var(--border-color);
  border-radius: 20px;
  font-size: 13px;
  color: var(--text-secondary);
  cursor: pointer;
  transition: var(--transition);
  user-select: none;
}
.tag:hover, .tag.active {
  background: rgba(255,87,34,0.12);
  border-color: var(--brand-primary);
  color: var(--brand-primary);
}

/* ============================================================
   20. 分享栏
   ============================================================ */
.share-bar {
  display: flex;
  align-items: center;
  gap: 10px;
  flex-wrap: wrap;
}
.share-label { font-size: 14px; color: var(--text-secondary); }
.share-btn {
  padding: 7px 16px;
  background: var(--bg-main);
  border: 1px solid var(--border-color);
  border-radius: 20px;
  color: var(--text-secondary);
  font-size: 13px;
  transition: var(--transition);
}
.share-btn:hover { border-color: var(--brand-primary); color: var(--brand-primary); }

/* ============================================================
   21. 页面Banner
   ============================================================ */
.page-banner {
  background: linear-gradient(135deg, var(--bg-card) 0%, var(--bg-main) 100%);
  border-bottom: 1px solid var(--border-color);
  padding: 60px 0;
  text-align: center;
}
.page-banner h1 {
  font-size: clamp(1.8rem, 4vw, 2.8rem);
  font-weight: 900;
  margin-bottom: 12px;
}
.page-banner p {
  color: var(--text-secondary);
  font-size: 1rem;
}

/* ============================================================
   22. 面包屑
   ============================================================ */
.breadcrumb {
  display: flex;
  align-items: center;
  gap: 8px;
  padding: 12px 0;
  font-size: 13px;
  color: var(--text-muted);
}
.breadcrumb a { color: var(--text-secondary); }
.breadcrumb a:hover { color: var(--brand-primary); }
.breadcrumb .sep { color: var(--text-muted); }
.breadcrumb .current { color: var(--text-primary); }

/* ============================================================
   23. 直播卡片
   ============================================================ */
.live-card {
  background: var(--bg-main);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-md);
  overflow: hidden;
  transition: var(--transition);
}
.live-card:hover {
  border-color: var(--border-hover);
  transform: translateY(-3px);
}
.live-thumb {
  position: relative;
  aspect-ratio: 16/9;
  overflow: hidden;
}
.live-thumb img { width: 100%; height: 100%; object-fit: cover; }
.live-badge {
  position: absolute;
  top: 8px;
  left: 8px;
  background: #f44336;
  color: #fff;
  font-size: 11px;
  font-weight: 700;
  padding: 3px 8px;
  border-radius: 4px;
  display: flex;
  align-items: center;
  gap: 5px;
}
.live-dot {
  width: 6px;
  height: 6px;
  background: #fff;
  border-radius: 50%;
  animation: pulse 1s infinite;
}
.live-info { padding: 12px 14px; }
.live-title { font-size: 13px; font-weight: 600; margin-bottom: 6px; }
.live-meta { font-size: 12px; color: var(--text-muted); }

/* ============================================================
   24. 时间线
   ============================================================ */
.timeline {
  max-width: 720px;
  margin: 0 auto;
  position: relative;
  padding-left: 32px;
}
.timeline::before {
  content: '';
  position: absolute;
  left: 0;
  top: 0;
  bottom: 0;
  width: 2px;
  background: linear-gradient(to bottom, var(--brand-primary), transparent);
}
.timeline-item {
  position: relative;
  padding: 0 0 36px 32px;
}
.timeline-item::before {
  content: '';
  position: absolute;
  left: -7px;
  top: 6px;
  width: 14px;
  height: 14px;
  background: var(--brand-primary);
  border-radius: 50%;
  border: 2px solid var(--bg-main);
  box-shadow: 0 0 0 3px rgba(255,87,34,0.2);
}
.timeline-year {
  font-size: 13px;
  font-weight: 800;
  color: var(--brand-primary);
  margin-bottom: 6px;
}
.timeline-content h4 {
  font-size: 15px;
  font-weight: 700;
  margin-bottom: 6px;
}
.timeline-content p {
  font-size: 14px;
  color: var(--text-secondary);
  line-height: 1.7;
}

/* ============================================================
   25. SEO文本区块
   ============================================================ */
.seo-text-block {
  padding: 40px 0;
  border-top: 1px solid var(--border-color);
}
.seo-text-block p {
  font-size: 14px;
  color: var(--text-muted);
  line-height: 1.9;
  margin-bottom: 12px;
  max-width: 900px;
}

/* ============================================================
   26. 页脚
   ============================================================ */
.site-footer {
  background: var(--bg-card);
  border-top: 1px solid var(--border-color);
  padding: 60px 0 0;
}

.footer-grid {
  display: grid;
  grid-template-columns: 2fr 1fr 1fr 1fr;
  gap: 40px;
  padding-bottom: 48px;
}

.footer-brand .logo-wrap {
  display: flex;
  align-items: center;
  gap: 10px;
  margin-bottom: 16px;
}
.footer-brand .logo-wrap img { width: 32px; height: 32px; border-radius: 6px; }
.footer-brand .logo-wrap span {
  font-size: 1.1rem;
  font-weight: 800;
  background: var(--brand-gradient);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}
.footer-brand p {
  font-size: 13px;
  color: var(--text-muted);
  line-height: 1.8;
  margin-bottom: 20px;
}
.footer-social {
  display: flex;
  gap: 10px;
}
.footer-social a {
  width: 36px;
  height: 36px;
  background: var(--bg-hover);
  border: 1px solid var(--border-color);
  border-radius: 8px;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 16px;
  transition: var(--transition);
}
.footer-social a:hover {
  border-color: var(--brand-primary);
  background: rgba(255,87,34,0.1);
}

.footer-col h4 {
  font-size: 14px;
  font-weight: 700;
  margin-bottom: 16px;
  color: var(--text-primary);
}
.footer-col ul { display: flex; flex-direction: column; gap: 8px; }
.footer-col ul li a {
  font-size: 13px;
  color: var(--text-muted);
  transition: var(--transition);
}
.footer-col ul li a:hover { color: var(--brand-primary); }

.footer-bottom {
  border-top: 1px solid var(--border-color);
  padding: 20px 0;
  display: flex;
  align-items: center;
  justify-content: space-between;
  flex-wrap: wrap;
  gap: 12px;
}
.footer-bottom p {
  font-size: 13px;
  color: var(--text-muted);
}
.update-time {
  color: var(--brand-primary) !important;
  font-weight: 600;
}
.footer-links {
  display: flex;
  gap: 16px;
  flex-wrap: wrap;
}
.footer-links a {
  font-size: 13px;
  color: var(--text-muted);
  transition: var(--transition);
}
.footer-links a:hover { color: var(--brand-primary); }

/* ============================================================
   27. 响应式媒体查询
   ============================================================ */
@media (max-width: 1024px) {
  .footer-grid { grid-template-columns: 1fr 1fr; }
  .footer-brand { grid-column: 1 / -1; }
  .media-intro-grid, .ai-intro-grid, .about-intro-grid { grid-template-columns: 1fr !important; }
}

@media (max-width: 768px) {
  .section { padding: 56px 0; }

  .main-nav {
    display: none;
    position: fixed;
    top: 64px;
    left: 0;
    right: 0;
    background: rgba(13,17,23,0.98);
    backdrop-filter: blur(16px);
    flex-direction: column;
    padding: 20px;
    border-bottom: 1px solid var(--border-color);
    gap: 4px;
    z-index: 199;
  }
  .main-nav.open { display: flex; }
  .main-nav a { width: 100%; padding: 12px 16px; }

  .hamburger { display: flex; }

  .header-search { display: none; }

  .hero-section { padding: 60px 0; min-height: auto; }
  .hero-btns { flex-direction: column; }
  .hero-stats { gap: 20px; }

  .video-grid { grid-template-columns: repeat(auto-fill, minmax(240px, 1fr)); }
  .expert-grid { grid-template-columns: repeat(auto-fill, minmax(240px, 1fr)); }
  .review-grid { grid-template-columns: 1fr; }

  .footer-grid { grid-template-columns: 1fr; gap: 24px; }
  .footer-bottom { flex-direction: column; text-align: center; }

  .howto-steps { grid-template-columns: 1fr 1fr; }
  .community-entries { grid-template-columns: repeat(3, 1fr); }
  .stats-row { grid-template-columns: repeat(2, 1fr); }

  .page-banner { padding: 40px 0; }
}

@media (max-width: 480px) {
  .container { padding: 0 16px; }
  .hero-content h1 { font-size: 2rem; }
  .howto-steps { grid-template-columns: 1fr; }
  .community-entries { grid-template-columns: repeat(2, 1fr); }
  .stats-row { grid-template-columns: repeat(2, 1fr); }
  .feature-grid { grid-template-columns: 1fr; }
  .ai-grid { grid-template-columns: 1fr; }
}

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

/* ============================================================
   29. 滚动条美化
   ============================================================ */
::-webkit-scrollbar { width: 6px; height: 6px; }
::-webkit-scrollbar-track { background: var(--bg-main); }
::-webkit-scrollbar-thumb { background: var(--bg-hover); border-radius: 3px; }
::-webkit-scrollbar-thumb:hover { background: var(--brand-primary); }