:root {
  --bg: #f6f7fb;
  --paper: #ffffff;
  --ink: #1d2533;
  --muted: #657084;
  --line: #e7eaf1;
  --brand: #202a44;
  --soft: #eef3ff;
  --accent: #d9472f;
  --radius: 18px;
  --shadow: 0 18px 45px rgba(31, 40, 58, .08);
}
* { box-sizing: border-box; }
html { scroll-behavior: smooth; }
body {
  margin: 0;
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC", "Microsoft YaHei", Arial, sans-serif;
  color: var(--ink);
  background: linear-gradient(180deg, #fbfcff 0%, var(--bg) 34%, #fff 100%);
  line-height: 1.65;
}
a { color: inherit; text-decoration: none; }
img { max-width: 100%; display: block; }
button, input { font: inherit; }
.site-header {
  position: sticky;
  top: 0;
  z-index: 50;
  background: rgba(255,255,255,.92);
  backdrop-filter: blur(18px);
  border-bottom: 1px solid var(--line);
}
.topbar, .main-nav, .search-panel, main, .site-footer { width: min(1200px, calc(100% - 32px)); margin: 0 auto; }
.topbar { display: flex; align-items: center; justify-content: space-between; padding: 16px 0 10px; gap: 18px; }
.brand-logo, .footer-logo { display: inline-flex; align-items: center; gap: 10px; font-weight: 900; letter-spacing: .02em; color: var(--brand); }
.brand-logo img, .footer-logo img { width: 44px; height: 44px; border-radius: 14px; object-fit: cover; box-shadow: var(--shadow); }
.brand-logo span, .footer-logo span { font-size: 24px; }
.domain-pill { padding: 8px 12px; border: 1px solid var(--line); border-radius: 999px; color: var(--muted); background: #fff; font-size: 14px; }
.main-nav { display: flex; gap: 8px; overflow-x: auto; padding: 0 0 10px; }
.main-nav a { white-space: nowrap; padding: 10px 14px; border-radius: 999px; color: var(--muted); font-weight: 700; }
.main-nav a:hover, .main-nav a.is-active { color: #fff; background: var(--brand); }
.search-panel { padding: 0 0 14px; }
.brand-search { background: var(--soft); border: 1px solid #dce6ff; border-radius: 18px; padding: 14px; }
.brand-search label { display: block; color: var(--brand); font-weight: 800; margin-bottom: 8px; }
.search-row { display: flex; gap: 8px; }
.search-row input { flex: 1; border: 1px solid var(--line); border-radius: 14px; padding: 12px 14px; outline: none; }
.search-row button, .primary-btn, .action-row button, .action-row a { border: none; border-radius: 14px; background: var(--brand); color: #fff; padding: 12px 16px; cursor: pointer; font-weight: 800; }
.search-notice { margin: 8px 0 0; color: var(--muted); font-size: 14px; }
main { padding: 28px 0 48px; }
.breadcrumb { display: flex; align-items: center; flex-wrap: wrap; gap: 8px; color: var(--muted); margin: 4px 0 18px; font-size: 14px; }
.breadcrumb a { color: var(--brand); font-weight: 700; }
.hero { display: grid; grid-template-columns: minmax(0, 1.2fr) minmax(280px, .8fr); gap: 24px; align-items: stretch; margin-bottom: 28px; }
.hero-copy, .hero-side, .section, .card, .video-card, .author-card, .comment-card, .faq-item { background: var(--paper); border: 1px solid var(--line); border-radius: var(--radius); box-shadow: var(--shadow); }
.hero-copy { padding: clamp(24px, 4vw, 48px); position: relative; overflow: hidden; }
.hero-copy::after { content: ""; position: absolute; right: -80px; top: -80px; width: 220px; height: 220px; border-radius: 50%; background: rgba(217,71,47,.08); }
.kicker { color: var(--accent); font-size: 14px; font-weight: 900; margin: 0 0 8px; }
h1 { font-size: clamp(30px, 5vw, 56px); line-height: 1.12; margin: 0 0 16px; color: var(--brand); }
h2 { color: var(--brand); line-height: 1.25; margin: 0 0 10px; font-size: clamp(22px, 3vw, 32px); }
h3 { color: var(--brand); line-height: 1.35; margin: 0 0 8px; font-size: 20px; }
p { margin: 0 0 12px; }
.hero-actions { display: flex; flex-wrap: wrap; gap: 10px; margin-top: 20px; }
.primary-btn.secondary { background: #fff; color: var(--brand); border: 1px solid var(--line); }
.hero-side { padding: 18px; }
.hero-side img { border-radius: 16px; width: 100%; aspect-ratio: 16/9; object-fit: cover; }
.image-description { color: var(--muted); font-size: 13px; margin-top: 10px; }
.section { padding: clamp(18px, 3vw, 28px); margin: 22px 0; }
.section-head { display: flex; align-items: end; justify-content: space-between; gap: 16px; margin-bottom: 18px; }
.section-subtitle { color: var(--muted); max-width: 760px; }
.more-link, .text-link { color: var(--accent); font-weight: 900; }
.module-grid { display: grid; grid-template-columns: repeat(3, minmax(0, 1fr)); gap: 16px; }
.module-card { padding: 18px; border: 1px solid var(--line); border-radius: 16px; background: linear-gradient(180deg, #fff, #fbfcff); }
.module-card ul { padding-left: 18px; margin: 10px 0; color: var(--muted); }
.hot-badge { display: inline-flex; margin-top: 8px; padding: 5px 10px; border-radius: 999px; color: var(--accent); background: #fff2ef; font-weight: 900; font-size: 13px; }
.video-grid { display: grid; grid-template-columns: repeat(2, minmax(0, 1fr)); gap: 18px; }
.video-card { overflow: hidden; }
.video-media { position: relative; background: #111827; overflow: hidden; }
.video-media img { width: 100%; aspect-ratio: 16/9; object-fit: cover; transition: transform .28s ease; }
.video-media video { position: absolute; inset: 0; width: 100%; height: 100%; opacity: 0; pointer-events: none; }
.play-button { position: absolute; left: 50%; top: 50%; transform: translate(-50%, -50%) scale(.92); width: 64px; height: 64px; border-radius: 50%; display: grid; place-items: center; background: rgba(255,255,255,.92); color: var(--accent); font-weight: 900; opacity: 0; transition: .25s ease; box-shadow: var(--shadow); }
.video-card:hover .play-button, .video-card:focus-within .play-button { opacity: 1; transform: translate(-50%, -50%) scale(1); }
.video-card:hover .video-media img { transform: scale(1.04); }
.rank-badge { position: absolute; left: 12px; top: 12px; color: #fff; background: rgba(32,42,68,.78); border: 1px solid rgba(255,255,255,.22); padding: 5px 10px; border-radius: 999px; font-weight: 900; font-size: 12px; }
.video-body { padding: 18px; }
.meta-line { display: flex; flex-wrap: wrap; gap: 8px 14px; color: var(--muted); font-size: 14px; margin: 12px 0; }
.stats-grid { display: grid; grid-template-columns: repeat(4, minmax(0, 1fr)); gap: 8px; margin: 12px 0; }
.stats-grid span { padding: 8px 10px; border-radius: 12px; background: var(--soft); color: var(--brand); font-weight: 800; font-size: 13px; text-align: center; }
.tag-row { display: flex; flex-wrap: wrap; gap: 8px; margin: 12px 0; }
.tag-row span { background: #f4f6fb; border: 1px solid var(--line); border-radius: 999px; padding: 5px 10px; color: var(--muted); font-size: 13px; }
.action-row { display: flex; flex-wrap: wrap; gap: 8px; margin-top: 14px; }
.action-row button, .action-row a { padding: 9px 12px; font-size: 14px; background: #f4f6fb; color: var(--brand); border: 1px solid var(--line); }
.author-grid { display: grid; grid-template-columns: repeat(2, minmax(0, 1fr)); gap: 16px; }
.author-card { display: grid; grid-template-columns: 96px minmax(0, 1fr); gap: 16px; padding: 18px; }
.author-card img { width: 96px; height: 96px; border-radius: 22px; object-fit: cover; }
.role { color: var(--accent); font-weight: 800; }
.category-grid, .share-grid, .contact-grid { display: grid; grid-template-columns: repeat(3, minmax(0, 1fr)); gap: 14px; }
.card { padding: 18px; }
.comment-list, .faq-list { display: grid; gap: 12px; }
.comment-card, .faq-item { padding: 16px; box-shadow: none; }
.comment-card header { display: flex; justify-content: space-between; gap: 12px; color: var(--muted); font-size: 14px; margin-bottom: 8px; }
.faq-item summary { cursor: pointer; font-weight: 900; color: var(--brand); }
.faq-item p { margin-top: 10px; color: var(--muted); }
.site-footer { margin-top: 32px; padding: 32px 0 16px; border-top: 1px solid var(--line); }
.footer-grid { display: grid; grid-template-columns: 1.2fr 1fr 1fr; gap: 18px; }
.copyright { margin-top: 18px; padding-top: 14px; border-top: 1px solid var(--line); color: var(--muted); font-size: 14px; }
.toast { position: fixed; left: 50%; bottom: 28px; transform: translateX(-50%); background: var(--brand); color: #fff; border-radius: 999px; padding: 12px 18px; box-shadow: var(--shadow); z-index: 100; opacity: 0; pointer-events: none; transition: .2s ease; }
.toast.is-visible { opacity: 1; }
@media (max-width: 900px) {
  .hero, .video-grid, .module-grid, .author-grid, .category-grid, .share-grid, .contact-grid, .footer-grid { grid-template-columns: 1fr; }
  .section-head { display: block; }
  .stats-grid { grid-template-columns: repeat(2, minmax(0, 1fr)); }
}
@media (max-width: 620px) {
  .topbar { align-items: flex-start; flex-direction: column; }
  .search-row { flex-direction: column; }
  .author-card { grid-template-columns: 1fr; }
  .author-card img { width: 100%; height: auto; aspect-ratio: 16/9; }
  .main-nav a { font-size: 14px; }
}