:root {
  --md-primary: #06b6d4; 
  --md-primary-hover: #0891b2;
  --md-bg: #f8fafc;
  --md-surface: #ffffff;
  --md-text-main: #0f172a;
  --md-text-muted: #64748b;
  --md-border: #e2e8f0;
  --md-header-bg: #0f172a;
  --md-elevation-1: 0 1px 3px rgba(15, 23, 42, 0.08), 0 1px 2px rgba(15, 23, 42, 0.04);
  --md-elevation-hover: 0 12px 24px -6px rgba(15, 23, 42, 0.12), 0 4px 10px -4px rgba(15, 23, 42, 0.08);
  --radius-sm: 8px; --radius-md: 12px; --radius-full: 9999px;
}
* { box-sizing: border-box; margin: 0; padding: 0; }
body { background: var(--md-bg); color: var(--md-text-main); font-family: 'Roboto', system-ui, -apple-system, sans-serif; line-height: 1.6; -webkit-font-smoothing: antialiased; }
a { color: inherit; text-decoration: none; transition: color 0.2s; }
a:hover { color: var(--md-primary); }
img { display: block; max-width: 100%; height: auto; }
button, input { font: inherit; outline: none; border: none; }
.seo-shell { width: min(1280px, calc(100% - 32px)); margin: 0 auto; }
.svg-icon { display: inline-block; vertical-align: middle; fill: currentColor; }

/* 顶部导航 */
.site-header { position: sticky; top: 0; z-index: 1000; background: var(--md-header-bg); color: #fff; box-shadow: 0 4px 6px -1px rgba(0,0,0,0.1); }
.site-header-row { height: 64px; display: flex; align-items: center; gap: 32px; }
.site-logo { font-size: 24px; font-weight: 800; letter-spacing: -0.5px; }
.site-logo strong { color: var(--md-primary); }
.site-nav { display: flex; flex: 1; gap: 8px; }
.site-nav a { padding: 8px 16px; border-radius: var(--radius-full); font-weight: 500; font-size: 15px; color: #cbd5e1; }
.site-nav a:hover { background: rgba(255,255,255,0.1); color: #fff; }
.header-actions { margin-left: auto; }
.menu-button { display: none; background: transparent; color: #fff; cursor: pointer; padding: 8px; border-radius: 50%; }
.menu-button:hover { background: rgba(255,255,255,0.1); }
.mobile-nav { display: none; padding: 8px 0 16px; border-top: 1px solid rgba(255,255,255,0.1); }
.mobile-nav a { display: block; padding: 12px 16px; color: #cbd5e1; border-radius: var(--radius-sm); margin-bottom: 4px; }
.mobile-nav a:hover { background: rgba(255,255,255,0.1); color: #fff; }

/* 广告与Hero搜索区 */
.ad-zone { margin: 24px auto; border-radius: var(--radius-md); overflow: hidden; background: var(--md-surface); box-shadow: var(--md-elevation-1); }
.hero { padding: 56px 0 48px; background: linear-gradient(135deg, #0f172a 0%, #1e293b 100%); color: #fff; text-align: center; }
.hero h1 { font-size: 36px; font-weight: 800; margin-bottom: 24px; letter-spacing: -1px; }
.hero h1 em { font-style: normal; color: var(--md-primary); }
.search-form { max-width: 680px; margin: 0 auto; display: flex; background: #fff; border-radius: var(--radius-full); padding: 4px; box-shadow: 0 8px 24px rgba(0,0,0,0.2); }
.search-form input { flex: 1; padding: 0 24px; font-size: 16px; border-radius: var(--radius-full) 0 0 var(--radius-full); background: transparent; color: var(--md-text-main); }
.search-form .md-btn { background: var(--md-primary); color: #fff; padding: 0 32px; height: 48px; border-radius: var(--radius-full); font-weight: 600; cursor: pointer; display: flex; align-items: center; gap: 8px; transition: background 0.2s; }
.search-form .md-btn:hover { background: var(--md-primary-hover); }
.hot-search { margin-top: 24px; display: flex; justify-content: center; align-items: center; flex-wrap: wrap; gap: 12px; font-size: 14px; }
.hot-search .badge { background: rgba(6,182,212,0.2); color: var(--md-primary); padding: 2px 8px; border-radius: 4px; font-weight: 600; font-size: 12px; }
.hot-search a { color: #94a3b8; }
.hot-search a:hover { color: #fff; text-decoration: underline; }

/* ================= 核心：强制一排 4 列图片视频矩阵 ================= */
.section { margin: 40px 0; }
.section-head { display: flex; justify-content: space-between; align-items: flex-end; margin-bottom: 24px; }
.section-head h2 { font-size: 24px; font-weight: 700; color: var(--md-text-main); display: flex; align-items: center; gap: 8px; }
.section-head h2::before { content: ''; display: block; width: 4px; height: 20px; background: var(--md-primary); border-radius: 4px; }
.section-head .more { display: flex; align-items: center; gap: 4px; font-weight: 500; color: var(--md-text-muted); }
.section-head .more:hover { color: var(--md-primary); }

.video-grid { 
  display: grid; 
  grid-template-columns: repeat(4, minmax(0, 1fr)); 
  gap: 24px; 
}
.video-card { background: var(--md-surface); border-radius: var(--radius-md); overflow: hidden; box-shadow: var(--md-elevation-1); transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1); cursor: pointer; display: flex; flex-direction: column; }
.video-card:hover { transform: translateY(-6px); box-shadow: var(--md-elevation-hover); }
.video-cover { position: relative; aspect-ratio: 16/9; background: #e2e8f0; overflow: hidden; }
.video-cover img { width: 100%; height: 100%; object-fit: cover; transition: transform 0.5s; }
.video-card:hover .video-cover img { transform: scale(1.05); }
.video-badge { position: absolute; top: 10px; left: 10px; background: rgba(6,182,212,0.9); color: #fff; font-size: 12px; font-weight: 600; padding: 4px 8px; border-radius: 4px; backdrop-filter: blur(4px); }
.video-count { position: absolute; bottom: 10px; right: 10px; background: rgba(15,23,42,0.75); color: #fff; font-size: 12px; padding: 4px 8px; border-radius: 4px; backdrop-filter: blur(4px); display: flex; align-items: center; gap: 4px; }
.video-title { padding: 14px 16px; margin: 0; font-size: 15px; font-weight: 500; line-height: 1.5; flex: 1; }
.video-title a { color: var(--md-text-main); display: -webkit-box; -webkit-line-clamp: 2; -webkit-box-orient: vertical; overflow: hidden; }
.video-card:hover .video-title a { color: var(--md-primary); }

/* 列表页与分页组件 */
.breadcrumb { margin: 24px 0; display: flex; align-items: center; gap: 8px; color: var(--md-text-muted); font-size: 14px; }
.page-title { font-size: 28px; font-weight: 700; margin-bottom: 24px; display: flex; align-items: center; gap: 12px; }
.page-title .chip { background: rgba(6,182,212,0.1); color: var(--md-primary); font-size: 14px; padding: 4px 12px; border-radius: var(--radius-full); }
.md-pagination { display: flex; flex-wrap: wrap; justify-content: center; align-items: center; gap: 8px; margin: 48px 0 24px; }
.md-pagination a, .md-pagination span { min-width: 40px; height: 40px; padding: 0 14px; display: inline-flex; align-items: center; justify-content: center; border-radius: var(--radius-full); background: var(--md-surface); color: var(--md-text-main); font-weight: 500; box-shadow: 0 1px 2px rgba(0,0,0,0.05); transition: all 0.2s; }
.md-pagination a:hover { background: var(--md-primary); color: #fff; }
.md-pagination .active { background: var(--md-primary); color: #fff; box-shadow: 0 4px 10px rgba(6,182,212,0.3); }
.md-pagination .summary { background: transparent; box-shadow: none; color: var(--md-text-muted); }

/* 详情页组件 */
.detail-layout { display: grid; grid-template-columns: minmax(0, 1fr) 320px; gap: 24px; margin: 24px 0; align-items: start; }
.md-card { background: var(--md-surface); border-radius: var(--radius-md); box-shadow: var(--md-elevation-1); overflow: hidden; }
.player-box { position: relative; aspect-ratio: 16/9; background: #000; }
.player-box iframe { width: 100%; height: 100%; border: 0; }
.detail-title { padding: 24px 24px 16px; font-size: 22px; font-weight: 600; line-height: 1.4; }
.detail-actions { padding: 0 24px 24px; display: flex; gap: 12px; }
.md-btn-outline { display: inline-flex; align-items: center; gap: 6px; padding: 0 20px; height: 40px; border-radius: 999px; font-weight: 500; cursor: pointer; transition: background 0.2s; background: rgba(6,182,212,0.1); color: var(--md-primary); border:none; }
.md-btn-outline:hover { background: rgba(6,182,212,0.2); }
.md-btn-filled { display: inline-flex; align-items: center; gap: 6px; padding: 0 20px; height: 40px; border-radius: 999px; font-weight: 500; cursor: pointer; transition: background 0.2s; background: var(--md-primary); color: #fff; border:none; }
.md-tabs { display: flex; border-bottom: 1px solid var(--md-border); padding: 0 12px; }
.md-tab-item { padding: 16px 20px; cursor: pointer; font-weight: 500; color: var(--md-text-muted); position: relative; transition: color 0.2s; }
.md-tab-item.active { color: var(--md-primary); }
.md-tab-item.active::after { content: ''; position: absolute; bottom: -1px; left: 0; width: 100%; height: 3px; background: var(--md-primary); border-radius: 3px 3px 0 0; }
.md-tab-content { padding: 24px; display: none; }
.md-tab-content.active { display: block; animation: fadeIn 0.3s; }
@keyframes fadeIn { from { opacity: 0; transform: translateY(5px); } to { opacity: 1; transform: translateY(0); } }
.meta-list { list-style: none; display: grid; grid-template-columns: repeat(auto-fill, minmax(200px, 1fr)); gap: 16px; margin-top: 16px; }
.meta-list li { display: flex; flex-direction: column; gap: 4px; }
.meta-list span { font-size: 13px; color: var(--md-text-muted); }
.meta-list strong { font-weight: 500; color: var(--md-text-main); }
.side-card { padding: 20px; }
.side-card h2 { font-size: 18px; margin-bottom: 16px; font-weight: 600; }
.side-item { display: grid; grid-template-columns: 120px 1fr; gap: 12px; margin-bottom: 16px; cursor: pointer; }
.side-item:hover h3 { color: var(--md-primary); }
.side-item .video-cover { aspect-ratio: 16/9; border-radius: 8px; overflow: hidden; background: #eee; }
.side-item h3 { font-size: 14px; font-weight: 500; line-height: 1.4; margin: 0; display: -webkit-box; -webkit-line-clamp: 3; -webkit-box-orient: vertical; overflow: hidden; }
.md-toast { position: fixed; bottom: 32px; left: 50%; transform: translateX(-50%) translateY(20px); background: #333; color: #fff; padding: 12px 24px; border-radius: 8px; font-weight: 500; opacity: 0; pointer-events: none; transition: all 0.3s; z-index: 9999; }
.md-toast.show { opacity: 1; transform: translateX(-50%) translateY(0); }

/* Footer & FAB */
.site-footer { background: var(--md-header-bg); color: #94a3b8; padding: 48px 0; margin-top: 64px; text-align: center; }
.footer-links { display: flex; justify-content: center; flex-wrap: wrap; gap: 24px; margin-bottom: 24px; }
.footer-links a { color: #cbd5e1; font-weight: 500; }
.site-footer p { margin-bottom: 8px; font-size: 14px; }
.fab-top { position: fixed; right: 24px; bottom: 24px; width: 56px; height: 56px; border-radius: var(--radius-full); background: var(--md-primary); color: #fff; display: flex; justify-content: center; align-items: center; box-shadow: 0 4px 12px rgba(6,182,212,0.4); cursor: pointer; transition: all 0.3s; opacity: 0; pointer-events: none; transform: scale(0.8); z-index: 99; }
.fab-top.show { opacity: 1; pointer-events: auto; transform: scale(1); }
.fab-top:hover { background: var(--md-primary-hover); transform: scale(1.05); }

/* 响应式降级 */
@media(max-width: 960px) {
  .site-nav { display: none; }
  .menu-button { display: block; margin-left: auto; }
  .mobile-nav.open { display: block; }
  .video-grid { grid-template-columns: repeat(3, minmax(0, 1fr)); } /* 平板3列 */
  .detail-layout { grid-template-columns: 1fr; } 
  .side-card { display: none; }
}
@media(max-width: 600px) {
  .video-grid { grid-template-columns: repeat(2, minmax(0, 1fr)); gap: 12px; } /* 手机2列 */
  .hero { padding: 40px 0 32px; }
  .hero h1 { font-size: 28px; }
  .search-form { display: flex; border-radius: var(--radius-sm); }
  .search-form input { border-radius: var(--radius-sm) 0 0 var(--radius-sm); padding: 0 16px; }
  .search-form .md-btn { border-radius: 0 var(--radius-sm) var(--radius-sm) 0; padding: 0 16px; }
  .md-pagination a, .md-pagination span { min-width: 36px; height: 36px; }
}