/* ===== 麻豆视频 - 主样式文件 ===== */
/* 品牌色彩体系 */
:root {
  --primary: #c0392b;
  --primary-dark: #96281b;
  --primary-light: #e74c3c;
  --accent: #e67e22;
  --accent-light: #f39c12;
  --bg-dark: #1a1a2e;
  --bg-mid: #16213e;
  --bg-card: #0f3460;
  --text-main: #2c3e50;
  --text-sub: #7f8c8d;
  --text-light: #ecf0f1;
  --border: #e0e0e0;
  --white: #ffffff;
  --shadow: 0 4px 20px rgba(0,0,0,0.12);
  --shadow-hover: 0 8px 32px rgba(192,57,43,0.22);
  --radius: 12px;
  --radius-sm: 6px;
  --transition: all 0.3s ease;
}

/* ===== 全局重置 ===== */
*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }
html { scroll-behavior: smooth; font-size: 16px; }
body {
  font-family: 'PingFang SC', 'Microsoft YaHei', '微软雅黑', 'Hiragino Sans GB', sans-serif;
  color: var(--text-main);
  background: #f8f9fa;
  line-height: 1.7;
  overflow-x: hidden;
}
a { text-decoration: none; color: inherit; transition: var(--transition); }
img { max-width: 100%; height: auto; display: block; }
ul, ol { list-style: none; }

/* ===== 顶部公告栏 ===== */
.top-bar {
  background: linear-gradient(90deg, var(--primary-dark), var(--bg-dark));
  color: var(--text-light);
  font-size: 13px;
  padding: 7px 0;
  text-align: center;
  letter-spacing: 0.5px;
}
.top-bar a { color: var(--accent-light); }
.top-bar a:hover { color: var(--white); }

/* ===== 导航栏 ===== */
.site-header {
  background: var(--white);
  box-shadow: 0 2px 16px rgba(0,0,0,0.09);
  position: sticky;
  top: 0;
  z-index: 1000;
}
.header-inner {
  max-width: 1280px;
  margin: 0 auto;
  padding: 0 20px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 70px;
}
.site-logo {
  display: flex;
  align-items: center;
  gap: 10px;
  font-size: 24px;
  font-weight: 800;
  color: var(--primary);
  letter-spacing: 1px;
}
.site-logo img {
  width: 44px;
  height: 44px;
  object-fit: contain;
  border-radius: 8px;
}
.site-logo .logo-text { color: var(--primary); }
.site-logo .logo-sub { font-size: 12px; color: var(--text-sub); font-weight: 400; display: block; line-height: 1; }

/* 主导航 */
.main-nav { display: flex; align-items: center; gap: 4px; }
.main-nav a {
  padding: 8px 14px;
  border-radius: var(--radius-sm);
  font-size: 15px;
  font-weight: 500;
  color: var(--text-main);
  white-space: nowrap;
  position: relative;
}
.main-nav a::after {
  content: '';
  position: absolute;
  bottom: 2px; left: 50%; right: 50%;
  height: 2px;
  background: var(--primary);
  transition: var(--transition);
}
.main-nav a:hover::after, .main-nav a.active::after { left: 14%; right: 14%; }
.main-nav a:hover, .main-nav a.active { color: var(--primary); }

/* 汉堡菜单 */
.nav-toggle { display: none; flex-direction: column; gap: 5px; cursor: pointer; padding: 8px; }
.nav-toggle span { display: block; width: 24px; height: 2px; background: var(--text-main); border-radius: 2px; transition: var(--transition); }

/* ===== 搜索框 ===== */
.search-bar-wrap {
  background: linear-gradient(135deg, #f8f9fa 0%, #fff 100%);
  border-bottom: 1px solid var(--border);
  padding: 14px 0;
}
.search-bar-inner {
  max-width: 1280px;
  margin: 0 auto;
  padding: 0 20px;
  display: flex;
  align-items: center;
  gap: 12px;
}
.search-form {
  display: flex;
  flex: 1;
  max-width: 640px;
  margin: 0 auto;
  border: 2px solid var(--primary);
  border-radius: 30px;
  overflow: hidden;
  background: var(--white);
  box-shadow: 0 2px 12px rgba(192,57,43,0.1);
}
.search-form input {
  flex: 1;
  border: none;
  outline: none;
  padding: 10px 20px;
  font-size: 15px;
  font-family: inherit;
  color: var(--text-main);
  background: transparent;
}
.search-form button {
  background: linear-gradient(135deg, var(--primary), var(--accent));
  color: var(--white);
  border: none;
  padding: 10px 24px;
  font-size: 15px;
  cursor: pointer;
  font-family: inherit;
  font-weight: 600;
  transition: var(--transition);
}
.search-form button:hover { background: linear-gradient(135deg, var(--primary-dark), var(--primary)); }
.search-tags { display: flex; gap: 8px; flex-wrap: wrap; }
.search-tag {
  font-size: 12px;
  color: var(--text-sub);
  padding: 3px 10px;
  border: 1px solid var(--border);
  border-radius: 20px;
  cursor: pointer;
  transition: var(--transition);
}
.search-tag:hover { color: var(--primary); border-color: var(--primary); }

/* ===== 面包屑 ===== */
.breadcrumb {
  max-width: 1280px;
  margin: 0 auto;
  padding: 12px 20px;
  font-size: 13px;
  color: var(--text-sub);
  display: flex;
  align-items: center;
  gap: 6px;
}
.breadcrumb a { color: var(--text-sub); }
.breadcrumb a:hover { color: var(--primary); }
.breadcrumb .sep { color: #bbb; }
.breadcrumb .current { color: var(--text-main); }

/* ===== Hero 横幅 ===== */
.hero-section {
  position: relative;
  background: var(--bg-dark);
  overflow: hidden;
  min-height: 520px;
  display: flex;
  align-items: center;
}
.hero-bg {
  position: absolute;
  inset: 0;
  background-size: cover;
  background-position: center;
  opacity: 0.45;
  filter: blur(1px);
}
.hero-overlay {
  position: absolute;
  inset: 0;
  background: linear-gradient(135deg, rgba(26,26,46,0.88) 0%, rgba(192,57,43,0.35) 100%);
}
.hero-content {
  position: relative;
  z-index: 2;
  max-width: 1280px;
  margin: 0 auto;
  padding: 60px 20px;
  color: var(--text-light);
}
.hero-content h1 {
  font-size: clamp(2rem, 5vw, 3.5rem);
  font-weight: 900;
  line-height: 1.2;
  margin-bottom: 18px;
  text-shadow: 0 2px 12px rgba(0,0,0,0.4);
}
.hero-content h1 span { color: var(--accent-light); }
.hero-content p {
  font-size: clamp(1rem, 2vw, 1.2rem);
  opacity: 0.9;
  max-width: 600px;
  margin-bottom: 32px;
  line-height: 1.8;
}
.hero-btns { display: flex; gap: 16px; flex-wrap: wrap; }
.btn {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 13px 28px;
  border-radius: 30px;
  font-size: 15px;
  font-weight: 600;
  cursor: pointer;
  transition: var(--transition);
  border: none;
  font-family: inherit;
}
.btn-primary {
  background: linear-gradient(135deg, var(--primary), var(--accent));
  color: var(--white);
  box-shadow: 0 4px 16px rgba(192,57,43,0.4);
}
.btn-primary:hover { transform: translateY(-2px); box-shadow: 0 8px 24px rgba(192,57,43,0.5); }
.btn-outline {
  background: transparent;
  color: var(--white);
  border: 2px solid rgba(255,255,255,0.7);
}
.btn-outline:hover { background: rgba(255,255,255,0.12); border-color: var(--white); }
.hero-stats {
  display: flex;
  gap: 40px;
  margin-top: 40px;
  flex-wrap: wrap;
}
.hero-stat { text-align: center; }
.hero-stat .num { font-size: 2rem; font-weight: 900; color: var(--accent-light); }
.hero-stat .label { font-size: 13px; opacity: 0.8; }

/* ===== 通用区块 ===== */
.section { padding: 70px 0; }
.section-alt { background: var(--white); }
.container { max-width: 1280px; margin: 0 auto; padding: 0 20px; }
.section-header { text-align: center; margin-bottom: 48px; }
.section-header h2 {
  font-size: clamp(1.6rem, 3vw, 2.4rem);
  font-weight: 800;
  color: var(--text-main);
  margin-bottom: 12px;
  position: relative;
  display: inline-block;
}
.section-header h2::after {
  content: '';
  display: block;
  width: 60px;
  height: 4px;
  background: linear-gradient(90deg, var(--primary), var(--accent));
  border-radius: 2px;
  margin: 10px auto 0;
}
.section-header p { color: var(--text-sub); font-size: 15px; max-width: 560px; margin: 0 auto; }

/* ===== 视频卡片网格 ===== */
.video-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
  gap: 24px;
}
.video-card {
  background: var(--white);
  border-radius: var(--radius);
  overflow: hidden;
  box-shadow: var(--shadow);
  transition: var(--transition);
  cursor: pointer;
}
.video-card:hover { transform: translateY(-6px); box-shadow: var(--shadow-hover); }
.video-thumb {
  position: relative;
  padding-top: 56.25%;
  overflow: hidden;
  background: #111;
}
.video-thumb img {
  position: absolute;
  inset: 0;
  width: 100%;
  height: 100%;
  object-fit: cover;
  transition: transform 0.4s ease;
}
.video-card:hover .video-thumb img { transform: scale(1.06); }
.play-btn {
  position: absolute;
  inset: 0;
  display: flex;
  align-items: center;
  justify-content: center;
  background: rgba(0,0,0,0);
  transition: var(--transition);
  opacity: 0;
}
.video-card:hover .play-btn { opacity: 1; background: rgba(0,0,0,0.35); }
.play-btn svg {
  width: 64px;
  height: 64px;
  filter: drop-shadow(0 2px 8px rgba(0,0,0,0.5));
  transform: scale(0.8);
  transition: var(--transition);
}
.video-card:hover .play-btn svg { transform: scale(1); }
.video-badge {
  position: absolute;
  top: 10px;
  left: 10px;
  background: var(--primary);
  color: var(--white);
  font-size: 11px;
  padding: 3px 8px;
  border-radius: 4px;
  font-weight: 600;
}
.video-duration {
  position: absolute;
  bottom: 8px;
  right: 8px;
  background: rgba(0,0,0,0.75);
  color: var(--white);
  font-size: 12px;
  padding: 2px 7px;
  border-radius: 4px;
}
.video-info { padding: 16px; }
.video-info h3 { font-size: 15px; font-weight: 700; margin-bottom: 8px; line-height: 1.4; color: var(--text-main); }
.video-info h3:hover { color: var(--primary); }
.video-meta { display: flex; align-items: center; gap: 14px; font-size: 13px; color: var(--text-sub); }
.video-meta span { display: flex; align-items: center; gap: 4px; }
.video-tags { display: flex; gap: 6px; flex-wrap: wrap; margin-top: 10px; }
.video-tag {
  font-size: 11px;
  padding: 2px 8px;
  background: #f0f0f0;
  border-radius: 20px;
  color: var(--text-sub);
}
.video-tag:hover { background: #fdecea; color: var(--primary); }

/* ===== 专家卡片 ===== */
.experts-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(240px, 1fr));
  gap: 28px;
}
.expert-card {
  background: var(--white);
  border-radius: var(--radius);
  padding: 28px 20px;
  text-align: center;
  box-shadow: var(--shadow);
  transition: var(--transition);
}
.expert-card:hover { transform: translateY(-4px); box-shadow: var(--shadow-hover); }
.expert-avatar {
  width: 90px;
  height: 90px;
  border-radius: 50%;
  object-fit: cover;
  margin: 0 auto 16px;
  border: 3px solid var(--primary);
}
.expert-name { font-size: 17px; font-weight: 700; margin-bottom: 4px; }
.expert-title { font-size: 13px; color: var(--primary); margin-bottom: 10px; }
.expert-desc { font-size: 13px; color: var(--text-sub); line-height: 1.6; margin-bottom: 16px; }
.expert-awards { display: flex; flex-wrap: wrap; gap: 6px; justify-content: center; margin-bottom: 16px; }
.award-badge {
  font-size: 11px;
  padding: 3px 8px;
  background: linear-gradient(135deg, #ffeaa7, #fdcb6e);
  border-radius: 20px;
  color: #6c4a00;
  font-weight: 600;
}
.expert-btns { display: flex; gap: 8px; justify-content: center; }
.btn-sm {
  padding: 7px 16px;
  font-size: 13px;
  border-radius: 20px;
  font-weight: 600;
  cursor: pointer;
  transition: var(--transition);
  border: none;
  font-family: inherit;
}
.btn-sm-primary { background: var(--primary); color: var(--white); }
.btn-sm-primary:hover { background: var(--primary-dark); }
.btn-sm-outline { background: transparent; color: var(--primary); border: 1.5px solid var(--primary); }
.btn-sm-outline:hover { background: var(--primary); color: var(--white); }

/* ===== 功能模块卡片 ===== */
.features-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(200px, 1fr));
  gap: 20px;
}
.feature-card {
  background: var(--white);
  border-radius: var(--radius);
  padding: 28px 20px;
  text-align: center;
  box-shadow: var(--shadow);
  transition: var(--transition);
  border-top: 3px solid transparent;
}
.feature-card:hover { border-top-color: var(--primary); transform: translateY(-4px); box-shadow: var(--shadow-hover); }
.feature-icon {
  width: 60px;
  height: 60px;
  border-radius: 50%;
  background: linear-gradient(135deg, #fdecea, #fce4e4);
  display: flex;
  align-items: center;
  justify-content: center;
  margin: 0 auto 16px;
  font-size: 28px;
}
.feature-card h3 { font-size: 15px; font-weight: 700; margin-bottom: 8px; }
.feature-card p { font-size: 13px; color: var(--text-sub); line-height: 1.6; }

/* ===== 统计数据 ===== */
.stats-section {
  background: linear-gradient(135deg, var(--bg-dark), var(--bg-mid));
  color: var(--text-light);
  padding: 60px 0;
}
.stats-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(180px, 1fr));
  gap: 32px;
  text-align: center;
}
.stat-item .num {
  font-size: 3rem;
  font-weight: 900;
  background: linear-gradient(135deg, var(--accent-light), var(--primary-light));
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}
.stat-item .label { font-size: 14px; opacity: 0.8; margin-top: 6px; }

/* ===== 合作品牌 ===== */
.partners-grid {
  display: flex;
  flex-wrap: wrap;
  gap: 20px;
  justify-content: center;
  align-items: center;
}
.partner-item {
  background: var(--white);
  border-radius: var(--radius-sm);
  padding: 16px 28px;
  font-size: 15px;
  font-weight: 700;
  color: var(--text-sub);
  box-shadow: var(--shadow);
  transition: var(--transition);
  border: 1px solid var(--border);
}
.partner-item:hover { color: var(--primary); border-color: var(--primary); transform: scale(1.04); }

/* ===== FAQ ===== */
.faq-list { max-width: 800px; margin: 0 auto; }
.faq-item {
  background: var(--white);
  border-radius: var(--radius);
  margin-bottom: 12px;
  box-shadow: var(--shadow);
  overflow: hidden;
}
.faq-question {
  padding: 18px 24px;
  font-size: 15px;
  font-weight: 700;
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 12px;
  transition: var(--transition);
  color: var(--text-main);
}
.faq-question:hover { color: var(--primary); }
.faq-question::after {
  content: '+';
  font-size: 22px;
  color: var(--primary);
  flex-shrink: 0;
  transition: var(--transition);
}
.faq-item.open .faq-question::after { content: '−'; }
.faq-answer {
  padding: 0 24px;
  max-height: 0;
  overflow: hidden;
  transition: max-height 0.4s ease, padding 0.3s ease;
  font-size: 14px;
  color: var(--text-sub);
  line-height: 1.8;
}
.faq-item.open .faq-answer { max-height: 300px; padding: 0 24px 18px; }

/* ===== 用户评价 ===== */
.reviews-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
  gap: 24px;
}
.review-card {
  background: var(--white);
  border-radius: var(--radius);
  padding: 24px;
  box-shadow: var(--shadow);
  transition: var(--transition);
  position: relative;
}
.review-card:hover { transform: translateY(-3px); box-shadow: var(--shadow-hover); }
.review-card::before {
  content: '"';
  position: absolute;
  top: 12px;
  right: 20px;
  font-size: 60px;
  color: #fdecea;
  font-family: Georgia, serif;
  line-height: 1;
}
.review-stars { color: #f1c40f; font-size: 16px; margin-bottom: 12px; }
.review-text { font-size: 14px; color: var(--text-sub); line-height: 1.8; margin-bottom: 16px; }
.reviewer { display: flex; align-items: center; gap: 12px; }
.reviewer-avatar {
  width: 42px;
  height: 42px;
  border-radius: 50%;
  background: linear-gradient(135deg, var(--primary), var(--accent));
  display: flex;
  align-items: center;
  justify-content: center;
  color: var(--white);
  font-size: 16px;
  font-weight: 700;
  flex-shrink: 0;
}
.reviewer-name { font-size: 14px; font-weight: 700; }
.reviewer-info { font-size: 12px; color: var(--text-sub); }

/* ===== 联系我们 ===== */
.contact-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 40px;
  align-items: start;
}
.contact-info h3 { font-size: 20px; font-weight: 800; margin-bottom: 20px; color: var(--text-main); }
.contact-item {
  display: flex;
  align-items: flex-start;
  gap: 14px;
  margin-bottom: 18px;
}
.contact-icon {
  width: 44px;
  height: 44px;
  border-radius: 50%;
  background: linear-gradient(135deg, #fdecea, #fce4e4);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 20px;
  flex-shrink: 0;
}
.contact-text .label { font-size: 12px; color: var(--text-sub); margin-bottom: 2px; }
.contact-text .value { font-size: 15px; font-weight: 600; color: var(--text-main); }
.qr-section { display: flex; gap: 24px; flex-wrap: wrap; }
.qr-item { text-align: center; }
.qr-item img { width: 130px; height: 130px; object-fit: cover; border-radius: var(--radius-sm); border: 2px solid var(--border); }
.qr-item p { font-size: 12px; color: var(--text-sub); margin-top: 8px; }

/* ===== 社交分享 ===== */
.share-bar {
  background: var(--white);
  border-top: 1px solid var(--border);
  padding: 18px 0;
}
.share-inner {
  max-width: 1280px;
  margin: 0 auto;
  padding: 0 20px;
  display: flex;
  align-items: center;
  gap: 16px;
  flex-wrap: wrap;
}
.share-label { font-size: 14px; color: var(--text-sub); font-weight: 600; }
.share-btns { display: flex; gap: 10px; flex-wrap: wrap; }
.share-btn {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  padding: 7px 16px;
  border-radius: 20px;
  font-size: 13px;
  font-weight: 600;
  cursor: pointer;
  transition: var(--transition);
  border: none;
  font-family: inherit;
}
.share-wechat { background: #07c160; color: var(--white); }
.share-weibo { background: #e6162d; color: var(--white); }
.share-douyin { background: #010101; color: var(--white); }
.share-bilibili { background: #00a1d6; color: var(--white); }
.share-btn:hover { opacity: 0.85; transform: scale(1.04); }

/* ===== 页脚 ===== */
.site-footer {
  background: var(--bg-dark);
  color: rgba(255,255,255,0.75);
  padding: 60px 0 0;
}
.footer-grid {
  display: grid;
  grid-template-columns: 2fr 1fr 1fr 1fr;
  gap: 40px;
  margin-bottom: 40px;
}
.footer-brand .site-logo { color: var(--white); margin-bottom: 16px; }
.footer-brand p { font-size: 14px; line-height: 1.8; opacity: 0.75; margin-bottom: 20px; }
.footer-col h4 { font-size: 15px; font-weight: 700; color: var(--white); margin-bottom: 16px; padding-bottom: 8px; border-bottom: 1px solid rgba(255,255,255,0.12); }
.footer-col a { display: block; font-size: 14px; margin-bottom: 8px; opacity: 0.7; }
.footer-col a:hover { opacity: 1; color: var(--accent-light); }
.footer-bottom {
  border-top: 1px solid rgba(255,255,255,0.1);
  padding: 20px;
  text-align: center;
  font-size: 13px;
  opacity: 0.6;
}
.footer-logo-img { width: 44px; height: 44px; object-fit: contain; border-radius: 8px; }

/* ===== 内页 Banner ===== */
.page-banner {
  background: linear-gradient(135deg, var(--bg-dark), var(--bg-mid));
  color: var(--text-light);
  padding: 60px 0;
  text-align: center;
  position: relative;
  overflow: hidden;
}
.page-banner::before {
  content: '';
  position: absolute;
  inset: 0;
  background: url('../images/hero_banner.jpg') center/cover no-repeat;
  opacity: 0.15;
}
.page-banner-content { position: relative; z-index: 2; }
.page-banner h1 { font-size: clamp(1.8rem, 4vw, 2.8rem); font-weight: 900; margin-bottom: 12px; }
.page-banner p { font-size: 15px; opacity: 0.85; max-width: 560px; margin: 0 auto; }

/* ===== 分页 ===== */
.pagination { display: flex; justify-content: center; gap: 8px; margin-top: 40px; flex-wrap: wrap; }
.page-btn {
  width: 38px;
  height: 38px;
  border-radius: var(--radius-sm);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 14px;
  font-weight: 600;
  cursor: pointer;
  transition: var(--transition);
  border: 1.5px solid var(--border);
  background: var(--white);
  color: var(--text-main);
}
.page-btn:hover, .page-btn.active { background: var(--primary); color: var(--white); border-color: var(--primary); }

/* ===== 侧边栏 ===== */
.page-layout { display: grid; grid-template-columns: 1fr 300px; gap: 32px; align-items: start; }
.sidebar { position: sticky; top: 90px; }
.sidebar-widget { background: var(--white); border-radius: var(--radius); padding: 20px; box-shadow: var(--shadow); margin-bottom: 24px; }
.sidebar-widget h4 { font-size: 15px; font-weight: 700; margin-bottom: 16px; padding-bottom: 10px; border-bottom: 2px solid var(--primary); color: var(--text-main); }
.hot-list li { padding: 10px 0; border-bottom: 1px solid var(--border); font-size: 14px; display: flex; align-items: center; gap: 10px; }
.hot-list li:last-child { border-bottom: none; }
.hot-num { width: 22px; height: 22px; border-radius: 4px; background: var(--border); display: flex; align-items: center; justify-content: center; font-size: 12px; font-weight: 700; flex-shrink: 0; }
.hot-num.top3 { background: var(--primary); color: var(--white); }
.hot-list a { flex: 1; color: var(--text-main); font-size: 13px; line-height: 1.4; }
.hot-list a:hover { color: var(--primary); }

/* ===== 标签云 ===== */
.tag-cloud { display: flex; flex-wrap: wrap; gap: 8px; }
.tag-cloud a {
  font-size: 12px;
  padding: 4px 12px;
  border-radius: 20px;
  background: #f0f0f0;
  color: var(--text-sub);
  transition: var(--transition);
}
.tag-cloud a:hover { background: var(--primary); color: var(--white); }

/* ===== 加入社区指南 ===== */
.how-to-steps { display: grid; grid-template-columns: repeat(auto-fill, minmax(200px, 1fr)); gap: 20px; }
.step-card {
  background: var(--white);
  border-radius: var(--radius);
  padding: 24px 20px;
  text-align: center;
  box-shadow: var(--shadow);
  position: relative;
}
.step-num {
  width: 44px;
  height: 44px;
  border-radius: 50%;
  background: linear-gradient(135deg, var(--primary), var(--accent));
  color: var(--white);
  font-size: 18px;
  font-weight: 900;
  display: flex;
  align-items: center;
  justify-content: center;
  margin: 0 auto 14px;
}
.step-card h4 { font-size: 15px; font-weight: 700; margin-bottom: 8px; }
.step-card p { font-size: 13px; color: var(--text-sub); line-height: 1.6; }

/* ===== 响应式 ===== */
@media (max-width: 1024px) {
  .footer-grid { grid-template-columns: 1fr 1fr; }
  .contact-grid { grid-template-columns: 1fr; }
  .page-layout { grid-template-columns: 1fr; }
  .sidebar { position: static; }
}
@media (max-width: 768px) {
  .main-nav { display: none; flex-direction: column; position: absolute; top: 70px; left: 0; right: 0; background: var(--white); box-shadow: 0 8px 24px rgba(0,0,0,0.12); padding: 16px; gap: 4px; }
  .main-nav.open { display: flex; }
  .nav-toggle { display: flex; }
  .hero-stats { gap: 24px; }
  .footer-grid { grid-template-columns: 1fr; }
  .video-grid { grid-template-columns: repeat(auto-fill, minmax(240px, 1fr)); }
  .experts-grid { grid-template-columns: repeat(auto-fill, minmax(200px, 1fr)); }
  .search-bar-inner { flex-direction: column; }
  .search-tags { justify-content: center; }
}
@media (max-width: 480px) {
  .video-grid { grid-template-columns: 1fr; }
  .hero-btns { flex-direction: column; }
  .btn { width: 100%; justify-content: center; }
}

/* ===== 懒加载占位 ===== */
img[data-src] { background: linear-gradient(90deg, #f0f0f0 25%, #e8e8e8 50%, #f0f0f0 75%); background-size: 200% 100%; animation: shimmer 1.5s infinite; }
@keyframes shimmer { 0% { background-position: -200% 0; } 100% { background-position: 200% 0; } }

/* ===== 滚动到顶部 ===== */
.back-top {
  position: fixed;
  bottom: 30px;
  right: 30px;
  width: 46px;
  height: 46px;
  background: linear-gradient(135deg, var(--primary), var(--accent));
  color: var(--white);
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  cursor: pointer;
  box-shadow: 0 4px 16px rgba(192,57,43,0.4);
  transition: var(--transition);
  opacity: 0;
  pointer-events: none;
  font-size: 20px;
  z-index: 999;
}
.back-top.visible { opacity: 1; pointer-events: auto; }
.back-top:hover { transform: translateY(-3px); box-shadow: 0 8px 24px rgba(192,57,43,0.5); }

/* ===== AI赋能区块 ===== */
.ai-section {
  background: linear-gradient(135deg, var(--bg-dark) 0%, #0f3460 100%);
  color: var(--text-light);
}
.ai-section .section-header h2 { color: var(--white); }
.ai-section .section-header h2::after { background: linear-gradient(90deg, var(--accent-light), var(--primary-light)); }
.ai-section .section-header p { color: rgba(255,255,255,0.7); }
.ai-card {
  background: rgba(255,255,255,0.07);
  border: 1px solid rgba(255,255,255,0.12);
  border-radius: var(--radius);
  padding: 28px 20px;
  text-align: center;
  transition: var(--transition);
  backdrop-filter: blur(8px);
}
.ai-card:hover { background: rgba(255,255,255,0.13); transform: translateY(-4px); }
.ai-card .feature-icon { background: rgba(255,255,255,0.1); }
.ai-card h3 { color: var(--white); font-size: 15px; font-weight: 700; margin-bottom: 8px; }
.ai-card p { color: rgba(255,255,255,0.7); font-size: 13px; line-height: 1.6; }

/* ===== 直播区块 ===== */
.live-badge {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  background: var(--primary);
  color: var(--white);
  font-size: 12px;
  font-weight: 700;
  padding: 4px 10px;
  border-radius: 20px;
  margin-bottom: 8px;
}
.live-dot {
  width: 8px;
  height: 8px;
  background: #fff;
  border-radius: 50%;
  animation: blink 1.2s infinite;
}
@keyframes blink { 0%, 100% { opacity: 1; } 50% { opacity: 0.2; } }

/* ===== 视频模态框 ===== */
.video-modal {
  display: none;
  position: fixed;
  inset: 0;
  background: rgba(0,0,0,0.88);
  z-index: 9999;
  align-items: center;
  justify-content: center;
}
.video-modal.open { display: flex; }
.modal-inner {
  background: #111;
  border-radius: var(--radius);
  overflow: hidden;
  max-width: 860px;
  width: 95%;
  position: relative;
}
.modal-close {
  position: absolute;
  top: 12px;
  right: 16px;
  color: var(--white);
  font-size: 28px;
  cursor: pointer;
  z-index: 2;
  line-height: 1;
}
.modal-video {
  width: 100%;
  aspect-ratio: 16/9;
  background: #000;
  display: flex;
  align-items: center;
  justify-content: center;
  color: rgba(255,255,255,0.6);
  font-size: 16px;
}
.modal-info { padding: 16px 20px; color: var(--text-light); }
.modal-info h3 { font-size: 17px; font-weight: 700; margin-bottom: 6px; }
.modal-info p { font-size: 13px; opacity: 0.7; }