/* 91网 - 主样式文件 */
/* 作者：91网前端团队 | 更新：2026-04 */

:root {
  --primary: #e8192c;
  --primary-dark: #c0121f;
  --primary-light: #ff4d5e;
  --secondary: #ff6b35;
  --text-main: #1a1a1a;
  --text-sub: #555;
  --text-light: #888;
  --bg-main: #f5f5f5;
  --bg-white: #ffffff;
  --bg-dark: #1a1a2e;
  --border: #e8e8e8;
  --shadow: 0 2px 12px rgba(0,0,0,0.08);
  --shadow-hover: 0 6px 24px rgba(232,25,44,0.15);
  --radius: 8px;
  --radius-lg: 12px;
  --transition: 0.25s ease;
}

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

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

body {
  font-family: -apple-system, BlinkMacSystemFont, "PingFang SC", "Microsoft YaHei", "Hiragino Sans GB", sans-serif;
  color: var(--text-main);
  background: var(--bg-main);
  line-height: 1.6;
}

a { color: inherit; text-decoration: none; }
a:hover { color: var(--primary); }
img { max-width: 100%; height: auto; display: block; }
ul, ol { list-style: none; }

.container { max-width: 1200px; margin: 0 auto; padding: 0 16px; }
.section { padding: 48px 0; }
.section-sm { padding: 32px 0; }

/* ===== 顶部公告栏 ===== */
.top-bar {
  background: var(--primary);
  color: #fff;
  font-size: 13px;
  padding: 6px 0;
  overflow: hidden;
}
.top-bar .container { display: flex; align-items: center; gap: 12px; }
.top-bar .bar-label {
  background: rgba(255,255,255,0.2);
  padding: 2px 10px;
  border-radius: 20px;
  white-space: nowrap;
  font-weight: 600;
}
.top-bar .bar-scroll { flex: 1; overflow: hidden; }
.top-bar .bar-scroll marquee { color: #ffe0e0; }

/* ===== 头部导航 ===== */
.site-header {
  background: var(--bg-white);
  box-shadow: 0 2px 8px rgba(0,0,0,0.06);
  position: sticky;
  top: 0;
  z-index: 100;
}
.header-inner {
  display: flex;
  align-items: center;
  gap: 24px;
  padding: 12px 0;
}
.site-logo {
  display: flex;
  align-items: center;
  gap: 10px;
  flex-shrink: 0;
}
.site-logo img {
  width: 44px;
  height: 44px;
  border-radius: 8px;
  object-fit: cover;
}
.logo-text { font-size: 22px; font-weight: 800; color: var(--primary); letter-spacing: -0.5px; }
.logo-sub { font-size: 11px; color: var(--text-light); }

.main-nav { display: flex; align-items: center; gap: 4px; flex: 1; }
.main-nav a {
  padding: 8px 14px;
  border-radius: var(--radius);
  font-size: 14px;
  font-weight: 500;
  color: var(--text-sub);
  transition: var(--transition);
  white-space: nowrap;
}
.main-nav a:hover, .main-nav a.active {
  background: #fff0f1;
  color: var(--primary);
}

.header-actions { display: flex; align-items: center; gap: 10px; flex-shrink: 0; }
.btn-login {
  background: var(--primary);
  color: #fff;
  padding: 8px 20px;
  border-radius: 20px;
  font-size: 14px;
  font-weight: 600;
  border: none;
  cursor: pointer;
  transition: var(--transition);
}
.btn-login:hover { background: var(--primary-dark); }
.btn-submit {
  background: transparent;
  color: var(--primary);
  border: 1.5px solid var(--primary);
  padding: 7px 18px;
  border-radius: 20px;
  font-size: 14px;
  font-weight: 600;
  cursor: pointer;
  transition: var(--transition);
}
.btn-submit:hover { background: #fff0f1; }

/* ===== 搜索框 ===== */
.search-bar {
  background: #fff8f8;
  border-bottom: 1px solid var(--border);
  padding: 12px 0;
}
.search-inner {
  display: flex;
  align-items: center;
  gap: 12px;
  max-width: 680px;
  margin: 0 auto;
}
.search-wrap {
  flex: 1;
  display: flex;
  align-items: center;
  background: #fff;
  border: 2px solid var(--primary);
  border-radius: 24px;
  overflow: hidden;
  padding: 0 16px;
}
.search-wrap input {
  flex: 1;
  border: none;
  outline: none;
  font-size: 14px;
  padding: 10px 0;
  background: transparent;
  color: var(--text-main);
}
.search-wrap input::placeholder { color: #bbb; }
.search-btn {
  background: var(--primary);
  color: #fff;
  border: none;
  padding: 10px 24px;
  font-size: 14px;
  font-weight: 600;
  cursor: pointer;
  border-radius: 0 22px 22px 0;
  margin-right: -16px;
  transition: var(--transition);
}
.search-btn:hover { background: var(--primary-dark); }
.search-hot { display: flex; align-items: center; gap: 8px; font-size: 12px; color: var(--text-light); }
.search-hot span { cursor: pointer; transition: var(--transition); }
.search-hot span:hover { color: var(--primary); }

/* ===== 面包屑 ===== */
.breadcrumb {
  background: var(--bg-white);
  padding: 10px 0;
  border-bottom: 1px solid var(--border);
  font-size: 13px;
  color: var(--text-light);
}
.breadcrumb a { color: var(--text-light); }
.breadcrumb a:hover { color: var(--primary); }
.breadcrumb span { margin: 0 6px; }

/* ===== 首页Banner ===== */
.hero-banner {
  position: relative;
  overflow: hidden;
  background: linear-gradient(135deg, #1a1a2e 0%, #16213e 50%, #0f3460 100%);
}
.hero-banner img {
  width: 100%;
  height: 420px;
  object-fit: cover;
  opacity: 0.7;
}
.hero-overlay {
  position: absolute;
  inset: 0;
  display: flex;
  flex-direction: column;
  justify-content: center;
  align-items: flex-start;
  padding: 0 80px;
  background: linear-gradient(90deg, rgba(0,0,0,0.7) 0%, rgba(0,0,0,0.2) 60%, transparent 100%);
}
.hero-tag {
  background: var(--primary);
  color: #fff;
  font-size: 12px;
  padding: 4px 12px;
  border-radius: 20px;
  margin-bottom: 16px;
  font-weight: 600;
}
.hero-title {
  font-size: 36px;
  font-weight: 800;
  color: #fff;
  line-height: 1.3;
  margin-bottom: 12px;
  text-shadow: 0 2px 8px rgba(0,0,0,0.3);
}
.hero-desc {
  font-size: 16px;
  color: rgba(255,255,255,0.85);
  margin-bottom: 24px;
  max-width: 500px;
}
.hero-btns { display: flex; gap: 12px; }
.btn-primary {
  background: var(--primary);
  color: #fff;
  padding: 12px 28px;
  border-radius: 24px;
  font-size: 15px;
  font-weight: 700;
  border: none;
  cursor: pointer;
  transition: var(--transition);
  display: inline-flex;
  align-items: center;
  gap: 6px;
}
.btn-primary:hover { background: var(--primary-dark); transform: translateY(-1px); box-shadow: var(--shadow-hover); }
.btn-outline {
  background: transparent;
  color: #fff;
  border: 2px solid rgba(255,255,255,0.6);
  padding: 11px 24px;
  border-radius: 24px;
  font-size: 15px;
  font-weight: 600;
  cursor: pointer;
  transition: var(--transition);
}
.btn-outline:hover { border-color: #fff; background: rgba(255,255,255,0.1); }

/* ===== 快捷导航 ===== */
.quick-nav {
  background: var(--bg-white);
  padding: 20px 0;
  border-bottom: 1px solid var(--border);
}
.quick-nav-list {
  display: flex;
  gap: 8px;
  flex-wrap: wrap;
  justify-content: center;
}
.quick-nav-item {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 6px;
  padding: 12px 20px;
  border-radius: var(--radius);
  cursor: pointer;
  transition: var(--transition);
  min-width: 80px;
}
.quick-nav-item:hover { background: #fff0f1; }
.quick-nav-item .icon { font-size: 24px; }
.quick-nav-item .label { font-size: 12px; color: var(--text-sub); font-weight: 500; }

/* ===== 模块标题 ===== */
.module-header {
  display: flex;
  align-items: flex-end;
  justify-content: space-between;
  margin-bottom: 24px;
  padding-bottom: 12px;
  border-bottom: 2px solid var(--border);
}
.module-header-left { display: flex; flex-direction: column; gap: 4px; }
.module-title {
  font-size: 22px;
  font-weight: 800;
  color: var(--text-main);
  display: flex;
  align-items: center;
  gap: 8px;
}
.module-title::before {
  content: '';
  display: inline-block;
  width: 4px;
  height: 22px;
  background: var(--primary);
  border-radius: 2px;
}
.module-subtitle { font-size: 13px; color: var(--text-light); }
.module-more {
  font-size: 13px;
  color: var(--primary);
  display: flex;
  align-items: center;
  gap: 4px;
  font-weight: 500;
}
.module-more:hover { text-decoration: underline; }

/* ===== 视频卡片 ===== */
.video-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 20px;
}
.video-grid-4 { grid-template-columns: repeat(4, 1fr); }
.video-grid-2 { grid-template-columns: repeat(2, 1fr); }

.video-card {
  background: var(--bg-white);
  border-radius: var(--radius-lg);
  overflow: hidden;
  box-shadow: var(--shadow);
  transition: var(--transition);
  cursor: pointer;
}
.video-card:hover {
  transform: translateY(-4px);
  box-shadow: var(--shadow-hover);
}
.video-thumb {
  position: relative;
  overflow: hidden;
  aspect-ratio: 16/9;
  background: #111;
}
.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(0,0,0,0.3);
  opacity: 0;
  transition: var(--transition);
}
.video-card:hover .video-play-btn { opacity: 1; }
.play-icon {
  width: 56px;
  height: 56px;
  background: rgba(232,25,44,0.9);
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  transition: transform 0.2s;
}
.play-icon:hover { transform: scale(1.1); }
.play-icon svg { width: 24px; height: 24px; fill: #fff; margin-left: 4px; }
.video-duration {
  position: absolute;
  bottom: 8px;
  right: 8px;
  background: rgba(0,0,0,0.75);
  color: #fff;
  font-size: 12px;
  padding: 2px 8px;
  border-radius: 4px;
  font-weight: 600;
}
.video-category-tag {
  position: absolute;
  top: 8px;
  left: 8px;
  background: var(--primary);
  color: #fff;
  font-size: 11px;
  padding: 2px 8px;
  border-radius: 4px;
  font-weight: 600;
}
.video-info { padding: 14px; }
.video-title {
  font-size: 14px;
  font-weight: 600;
  color: var(--text-main);
  line-height: 1.5;
  margin-bottom: 8px;
  display: -webkit-box;
  -webkit-line-clamp: 2;
  -webkit-box-orient: vertical;
  overflow: hidden;
}
.video-meta {
  display: flex;
  align-items: center;
  justify-content: space-between;
  font-size: 12px;
  color: var(--text-light);
}
.video-author { display: flex; align-items: center; gap: 4px; }
.video-stats { display: flex; align-items: center; gap: 10px; }
.video-stats span { display: flex; align-items: center; gap: 3px; }

/* ===== 资讯列表 ===== */
.news-list { display: flex; flex-direction: column; gap: 16px; }
.news-item {
  background: var(--bg-white);
  border-radius: var(--radius);
  padding: 16px;
  display: flex;
  gap: 16px;
  box-shadow: var(--shadow);
  transition: var(--transition);
}
.news-item:hover { box-shadow: var(--shadow-hover); transform: translateX(4px); }
.news-thumb {
  width: 120px;
  height: 80px;
  border-radius: var(--radius);
  overflow: hidden;
  flex-shrink: 0;
}
.news-thumb img { width: 100%; height: 100%; object-fit: cover; }
.news-content { flex: 1; }
.news-title {
  font-size: 15px;
  font-weight: 600;
  color: var(--text-main);
  margin-bottom: 6px;
  line-height: 1.5;
}
.news-title:hover { color: var(--primary); }
.news-desc { font-size: 13px; color: var(--text-sub); margin-bottom: 8px; line-height: 1.5; }
.news-footer { display: flex; align-items: center; gap: 12px; font-size: 12px; color: var(--text-light); }
.news-tag {
  background: #fff0f1;
  color: var(--primary);
  padding: 2px 8px;
  border-radius: 4px;
  font-size: 11px;
  font-weight: 600;
}

/* ===== 专题卡片 ===== */
.topic-grid { display: grid; grid-template-columns: repeat(3, 1fr); gap: 20px; }
.topic-card {
  background: var(--bg-white);
  border-radius: var(--radius-lg);
  overflow: hidden;
  box-shadow: var(--shadow);
  transition: var(--transition);
}
.topic-card:hover { transform: translateY(-3px); box-shadow: var(--shadow-hover); }
.topic-cover {
  height: 140px;
  background: linear-gradient(135deg, var(--primary) 0%, var(--secondary) 100%);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 48px;
  position: relative;
  overflow: hidden;
}
.topic-cover img { width: 100%; height: 100%; object-fit: cover; }
.topic-body { padding: 16px; }
.topic-title { font-size: 16px; font-weight: 700; margin-bottom: 6px; }
.topic-desc { font-size: 13px; color: var(--text-sub); margin-bottom: 10px; }
.topic-stats { display: flex; gap: 12px; font-size: 12px; color: var(--text-light); }

/* ===== 作者卡片 ===== */
.author-grid { display: grid; grid-template-columns: repeat(5, 1fr); gap: 16px; }
.author-card {
  background: var(--bg-white);
  border-radius: var(--radius-lg);
  padding: 20px 16px;
  text-align: center;
  box-shadow: var(--shadow);
  transition: var(--transition);
}
.author-card:hover { transform: translateY(-3px); box-shadow: var(--shadow-hover); }
.author-avatar {
  width: 72px;
  height: 72px;
  border-radius: 50%;
  object-fit: cover;
  margin: 0 auto 10px;
  border: 3px solid var(--border);
}
.author-name { font-size: 14px; font-weight: 700; margin-bottom: 4px; }
.author-title { font-size: 11px; color: var(--primary); margin-bottom: 8px; }
.author-stats { display: flex; justify-content: center; gap: 16px; font-size: 12px; color: var(--text-light); }
.author-stats .stat { display: flex; flex-direction: column; align-items: center; }
.author-stats .num { font-size: 15px; font-weight: 700; color: var(--text-main); }
.btn-follow {
  margin-top: 12px;
  width: 100%;
  padding: 7px;
  border: 1.5px solid var(--primary);
  color: var(--primary);
  border-radius: 20px;
  font-size: 13px;
  font-weight: 600;
  cursor: pointer;
  background: transparent;
  transition: var(--transition);
}
.btn-follow:hover { background: var(--primary); color: #fff; }

/* ===== FAQ ===== */
.faq-list { display: flex; flex-direction: column; gap: 12px; }
.faq-item {
  background: var(--bg-white);
  border-radius: var(--radius);
  overflow: hidden;
  box-shadow: var(--shadow);
}
.faq-q {
  padding: 16px 20px;
  font-size: 15px;
  font-weight: 600;
  cursor: pointer;
  display: flex;
  justify-content: space-between;
  align-items: center;
  transition: var(--transition);
}
.faq-q:hover { color: var(--primary); }
.faq-q .arrow { transition: transform 0.3s; font-size: 12px; color: var(--text-light); }
.faq-item.open .faq-q .arrow { transform: rotate(180deg); }
.faq-a {
  padding: 0 20px;
  max-height: 0;
  overflow: hidden;
  transition: max-height 0.35s ease, padding 0.35s ease;
  font-size: 14px;
  color: var(--text-sub);
  line-height: 1.7;
  border-top: 0 solid var(--border);
}
.faq-item.open .faq-a {
  max-height: 300px;
  padding: 14px 20px 18px;
  border-top-width: 1px;
}

/* ===== 评论区 ===== */
.comment-list { display: flex; flex-direction: column; gap: 16px; }
.comment-item {
  background: var(--bg-white);
  border-radius: var(--radius);
  padding: 18px;
  box-shadow: var(--shadow);
}
.comment-header { display: flex; align-items: center; gap: 10px; margin-bottom: 10px; }
.comment-avatar {
  width: 40px;
  height: 40px;
  border-radius: 50%;
  background: var(--primary);
  color: #fff;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 18px;
  flex-shrink: 0;
}
.comment-user { font-size: 14px; font-weight: 600; }
.comment-date { font-size: 12px; color: var(--text-light); margin-left: auto; }
.comment-stars { color: #f5a623; font-size: 13px; }
.comment-body { font-size: 14px; color: var(--text-sub); line-height: 1.7; margin-bottom: 10px; }
.comment-footer { display: flex; align-items: center; gap: 16px; font-size: 12px; color: var(--text-light); }
.comment-action { cursor: pointer; display: flex; align-items: center; gap: 4px; transition: var(--transition); }
.comment-action:hover { color: var(--primary); }
.verified-badge {
  background: #e8f5e9;
  color: #2e7d32;
  font-size: 11px;
  padding: 1px 6px;
  border-radius: 4px;
  font-weight: 600;
}

/* ===== 互动功能栏 ===== */
.interact-bar {
  background: var(--bg-white);
  border-radius: var(--radius);
  padding: 16px 20px;
  display: flex;
  align-items: center;
  gap: 20px;
  box-shadow: var(--shadow);
  flex-wrap: wrap;
}
.interact-btn {
  display: flex;
  align-items: center;
  gap: 6px;
  padding: 8px 16px;
  border-radius: 20px;
  font-size: 14px;
  cursor: pointer;
  border: 1.5px solid var(--border);
  background: transparent;
  color: var(--text-sub);
  transition: var(--transition);
  font-weight: 500;
}
.interact-btn:hover { border-color: var(--primary); color: var(--primary); background: #fff0f1; }
.interact-btn.liked { background: #fff0f1; color: var(--primary); border-color: var(--primary); }

/* ===== 帮助中心 ===== */
.help-grid { display: grid; grid-template-columns: repeat(4, 1fr); gap: 16px; }
.help-card {
  background: var(--bg-white);
  border-radius: var(--radius);
  padding: 20px;
  text-align: center;
  box-shadow: var(--shadow);
  transition: var(--transition);
  cursor: pointer;
}
.help-card:hover { transform: translateY(-2px); box-shadow: var(--shadow-hover); }
.help-icon { font-size: 32px; margin-bottom: 10px; }
.help-title { font-size: 14px; font-weight: 600; margin-bottom: 6px; }
.help-desc { font-size: 12px; color: var(--text-light); }

/* ===== 联系我们 ===== */
.contact-grid { display: grid; grid-template-columns: repeat(3, 1fr); gap: 20px; }
.contact-card {
  background: var(--bg-white);
  border-radius: var(--radius-lg);
  padding: 24px;
  text-align: center;
  box-shadow: var(--shadow);
}
.contact-icon { font-size: 40px; margin-bottom: 12px; }
.contact-title { font-size: 16px; font-weight: 700; margin-bottom: 8px; }
.contact-info { font-size: 14px; color: var(--text-sub); line-height: 1.7; }

/* ===== 统计数字 ===== */
.stats-bar {
  background: linear-gradient(135deg, var(--primary) 0%, var(--secondary) 100%);
  padding: 32px 0;
}
.stats-grid { display: grid; grid-template-columns: repeat(4, 1fr); gap: 20px; text-align: center; }
.stat-item { color: #fff; }
.stat-num { font-size: 36px; font-weight: 800; line-height: 1; margin-bottom: 6px; }
.stat-label { font-size: 14px; opacity: 0.85; }

/* ===== 侧边栏 ===== */
.sidebar { display: flex; flex-direction: column; gap: 20px; }
.sidebar-widget {
  background: var(--bg-white);
  border-radius: var(--radius-lg);
  overflow: hidden;
  box-shadow: var(--shadow);
}
.widget-header {
  background: linear-gradient(90deg, var(--primary) 0%, var(--primary-light) 100%);
  color: #fff;
  padding: 12px 16px;
  font-size: 15px;
  font-weight: 700;
}
.widget-body { padding: 16px; }
.hot-list { display: flex; flex-direction: column; gap: 10px; }
.hot-item { display: flex; align-items: flex-start; gap: 10px; }
.hot-rank {
  width: 22px;
  height: 22px;
  border-radius: 4px;
  background: var(--border);
  color: var(--text-light);
  font-size: 12px;
  font-weight: 700;
  display: flex;
  align-items: center;
  justify-content: center;
  flex-shrink: 0;
}
.hot-rank.top1 { background: #e8192c; color: #fff; }
.hot-rank.top2 { background: #ff6b35; color: #fff; }
.hot-rank.top3 { background: #f5a623; color: #fff; }
.hot-title { font-size: 13px; color: var(--text-sub); line-height: 1.5; cursor: pointer; }
.hot-title:hover { color: var(--primary); }

/* ===== 页脚 ===== */
.site-footer {
  background: var(--bg-dark);
  color: rgba(255,255,255,0.7);
  padding: 48px 0 0;
  margin-top: 48px;
}
.footer-grid { display: grid; grid-template-columns: 2fr 1fr 1fr 1fr; gap: 40px; margin-bottom: 40px; }
.footer-brand .logo-text { color: #fff; font-size: 24px; margin-bottom: 12px; }
.footer-brand p { font-size: 13px; line-height: 1.8; }
.footer-col h4 { color: #fff; font-size: 15px; font-weight: 700; margin-bottom: 16px; }
.footer-col ul { display: flex; flex-direction: column; gap: 8px; }
.footer-col ul li a { font-size: 13px; color: rgba(255,255,255,0.6); transition: var(--transition); }
.footer-col ul li a:hover { color: var(--primary); }
.footer-bottom {
  border-top: 1px solid rgba(255,255,255,0.1);
  padding: 20px 0;
  display: flex;
  align-items: center;
  justify-content: space-between;
  font-size: 13px;
  color: rgba(255,255,255,0.4);
}
.footer-links { display: flex; gap: 16px; }
.footer-links a { color: rgba(255,255,255,0.4); transition: var(--transition); }
.footer-links a:hover { color: var(--primary); }

/* ===== 标签云 ===== */
.tag-cloud { display: flex; flex-wrap: wrap; gap: 8px; }
.tag {
  background: #f5f5f5;
  color: var(--text-sub);
  padding: 4px 12px;
  border-radius: 20px;
  font-size: 12px;
  cursor: pointer;
  transition: var(--transition);
}
.tag:hover { background: #fff0f1; color: var(--primary); }
.tag.hot { background: #fff0f1; color: var(--primary); }

/* ===== 分页 ===== */
.pagination { display: flex; justify-content: center; align-items: center; gap: 8px; margin-top: 32px; }
.page-btn {
  width: 36px;
  height: 36px;
  border-radius: var(--radius);
  border: 1.5px solid var(--border);
  background: var(--bg-white);
  color: var(--text-sub);
  font-size: 14px;
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: center;
  transition: var(--transition);
}
.page-btn:hover, .page-btn.active { background: var(--primary); color: #fff; border-color: var(--primary); }

/* ===== 通知Toast ===== */
.toast {
  position: fixed;
  bottom: 24px;
  left: 50%;
  transform: translateX(-50%) translateY(100px);
  background: rgba(0,0,0,0.8);
  color: #fff;
  padding: 12px 24px;
  border-radius: 24px;
  font-size: 14px;
  z-index: 9999;
  transition: transform 0.3s ease;
}
.toast.show { transform: translateX(-50%) translateY(0); }

/* ===== 响应式 ===== */
@media (max-width: 1024px) {
  .video-grid { grid-template-columns: repeat(2, 1fr); }
  .video-grid-4 { grid-template-columns: repeat(2, 1fr); }
  .author-grid { grid-template-columns: repeat(3, 1fr); }
  .footer-grid { grid-template-columns: 1fr 1fr; }
  .stats-grid { grid-template-columns: repeat(2, 1fr); }
}

@media (max-width: 768px) {
  .hero-banner img { height: 240px; }
  .hero-overlay { padding: 0 24px; }
  .hero-title { font-size: 22px; }
  .hero-desc { font-size: 14px; }
  .main-nav { display: none; }
  .video-grid { grid-template-columns: 1fr; }
  .topic-grid { grid-template-columns: repeat(2, 1fr); }
  .author-grid { grid-template-columns: repeat(2, 1fr); }
  .help-grid { grid-template-columns: repeat(2, 1fr); }
  .contact-grid { grid-template-columns: 1fr; }
  .footer-grid { grid-template-columns: 1fr; }
  .footer-bottom { flex-direction: column; gap: 8px; text-align: center; }
  .stats-grid { grid-template-columns: repeat(2, 1fr); }
  .container { padding: 0 12px; }
}

/* ===== 懒加载占位 ===== */
img[data-src] { background: #f0f0f0; }

/* ===== 内页布局 ===== */
.page-layout { display: grid; grid-template-columns: 1fr 300px; gap: 24px; }
@media (max-width: 900px) { .page-layout { grid-template-columns: 1fr; } }

.page-main {}
.page-sidebar {}

/* ===== 内容详情 ===== */
.article-header { margin-bottom: 24px; }
.article-title { font-size: 26px; font-weight: 800; line-height: 1.4; margin-bottom: 12px; }
.article-meta { display: flex; flex-wrap: wrap; gap: 12px; font-size: 13px; color: var(--text-light); align-items: center; }
.article-body { font-size: 15px; line-height: 1.9; color: var(--text-sub); }
.article-body p { margin-bottom: 16px; }
.article-body h2 { font-size: 20px; font-weight: 700; color: var(--text-main); margin: 24px 0 12px; }
.article-body h3 { font-size: 17px; font-weight: 700; color: var(--text-main); margin: 20px 0 10px; }

/* ===== 视频播放器 ===== */
.video-player-wrap {
  background: #000;
  border-radius: var(--radius-lg);
  overflow: hidden;
  aspect-ratio: 16/9;
  position: relative;
  cursor: pointer;
}
.video-player-wrap video { width: 100%; height: 100%; }
.video-player-overlay {
  position: absolute;
  inset: 0;
  display: flex;
  align-items: center;
  justify-content: center;
  background: rgba(0,0,0,0.4);
  transition: var(--transition);
}
.video-player-wrap:hover .video-player-overlay { background: rgba(0,0,0,0.2); }
.big-play-btn {
  width: 80px;
  height: 80px;
  background: rgba(232,25,44,0.9);
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  transition: transform 0.2s;
}
.big-play-btn:hover { transform: scale(1.1); }
.big-play-btn svg { width: 36px; height: 36px; fill: #fff; margin-left: 6px; }

/* ===== 移动端菜单 ===== */
.mobile-menu-btn {
  display: none;
  background: none;
  border: none;
  font-size: 24px;
  cursor: pointer;
  color: var(--text-main);
}
@media (max-width: 768px) { .mobile-menu-btn { display: block; } }

/* ===== 返回顶部 ===== */
.back-top {
  position: fixed;
  bottom: 24px;
  right: 24px;
  width: 44px;
  height: 44px;
  background: var(--primary);
  color: #fff;
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  cursor: pointer;
  box-shadow: 0 4px 12px rgba(232,25,44,0.4);
  opacity: 0;
  transform: translateY(20px);
  transition: var(--transition);
  z-index: 99;
  font-size: 18px;
}
.back-top.show { opacity: 1; transform: translateY(0); }
.back-top:hover { background: var(--primary-dark); }