:root {
  --ink: #0f172a;
  --muted: #64748b;
  --line: #e2e8f0;
  --paper: #ffffff;
  --soft: #f8fafc;
  --brand: #0ea5e9;
  --brand-dark: #0369a1;
  --accent: #ec4899;
  --good: #10b981;
  --radius: 24px;
  --shadow: 0 20px 45px rgba(15, 23, 42, 0.08);
}
* { box-sizing: border-box; }
html { scroll-behavior: smooth; }
body {
  margin: 0;
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC", "Microsoft YaHei", sans-serif;
  color: var(--ink);
  background: linear-gradient(180deg, #f8fbff 0%, #ffffff 45%, #f8fafc 100%);
  line-height: 1.75;
}
a { color: inherit; text-decoration: none; }
img { max-width: 100%; height: auto; display: block; }
.container { width: min(1160px, calc(100% - 32px)); margin: 0 auto; }
.sr-only { position: absolute; width: 1px; height: 1px; padding: 0; margin: -1px; overflow: hidden; clip: rect(0,0,0,0); border: 0; }
.site-header {
  position: sticky;
  top: 0;
  z-index: 20;
  background: rgba(255, 255, 255, 0.92);
  backdrop-filter: blur(18px);
  border-bottom: 1px solid rgba(226,232,240,0.9);
}
.header-inner { display: flex; align-items: center; justify-content: space-between; gap: 24px; padding: 14px 0; }
.brand-logo { display: inline-flex; align-items: center; gap: 10px; font-weight: 900; font-size: 22px; letter-spacing: -0.03em; }
.brand-logo img { width: 112px; }
.main-nav { display: flex; flex-wrap: wrap; gap: 10px; justify-content: flex-end; }
.main-nav a { padding: 9px 12px; border-radius: 999px; color: #334155; font-size: 14px; }
.main-nav a:hover, .main-nav a:focus { background: #e0f2fe; color: var(--brand-dark); }
.search-bar-wrap { padding: 0 0 14px; }
.search-box { display: grid; grid-template-columns: 1fr auto; gap: 10px; }
.search-box input { width: 100%; border: 1px solid var(--line); border-radius: 999px; padding: 12px 16px; font-size: 15px; background: var(--soft); }
.search-box button, .primary-button, .secondary-button, .share-button { border: 0; border-radius: 999px; padding: 12px 18px; cursor: pointer; font-weight: 700; }
.search-box button, .primary-button, .share-button { background: var(--ink); color: white; }
.secondary-button { background: #e0f2fe; color: var(--brand-dark); }
.search-tip { margin: 8px 0 0; color: var(--muted); font-size: 13px; }
.hero { padding: 72px 0 48px; }
.hero-grid { display: grid; grid-template-columns: minmax(0, 1.04fr) minmax(320px, 0.96fr); gap: 36px; align-items: center; }
.eyebrow { display: inline-flex; align-items: center; gap: 8px; color: var(--brand-dark); background: #e0f2fe; padding: 6px 12px; border-radius: 999px; font-weight: 700; font-size: 14px; }
h1, h2, h3 { line-height: 1.22; }
h1 { font-size: clamp(36px, 6vw, 64px); margin: 18px 0 18px; letter-spacing: -0.04em; }
h2 { font-size: clamp(26px, 3.8vw, 40px); margin: 0 0 16px; letter-spacing: -0.03em; }
h3 { font-size: 21px; margin: 0 0 8px; }
.lead { font-size: 18px; color: #475569; max-width: 780px; }
.hero-actions { display: flex; flex-wrap: wrap; gap: 12px; margin: 28px 0; }
.hero-metrics { display: grid; grid-template-columns: repeat(3, 1fr); gap: 12px; margin-top: 24px; }
.metric-card { background: var(--paper); border: 1px solid var(--line); border-radius: 20px; padding: 18px; box-shadow: 0 8px 24px rgba(15,23,42,.05); }
.metric-card strong { display: block; font-size: 24px; }
.metric-card span { color: var(--muted); font-size: 13px; }
.hero-figure { position: relative; }
.hero-figure img, .feature-image img { border-radius: 32px; box-shadow: var(--shadow); }
.domain-caption { margin: 10px 0 0; color: var(--muted); font-size: 13px; }
.section { padding: 58px 0; }
.section-heading { display: grid; grid-template-columns: 0.8fr 1.2fr; gap: 24px; align-items: end; margin-bottom: 28px; }
.section-heading p { margin: 0; color: var(--muted); }
.cards { display: grid; grid-template-columns: repeat(3, 1fr); gap: 18px; }
.card { background: var(--paper); border: 1px solid var(--line); border-radius: var(--radius); padding: 22px; box-shadow: 0 12px 32px rgba(15,23,42,0.05); }
.card p { color: var(--muted); }
.tag-list { display: flex; flex-wrap: wrap; gap: 8px; margin: 14px 0 0; }
.tag { border: 1px solid #bae6fd; background: #f0f9ff; color: var(--brand-dark); padding: 5px 10px; border-radius: 999px; font-size: 13px; }
.feature-grid { display: grid; grid-template-columns: 0.9fr 1.1fr; gap: 28px; align-items: center; }
.check-list { list-style: none; padding: 0; margin: 18px 0 0; }
.check-list li { position: relative; padding-left: 30px; margin: 12px 0; }
.check-list li::before { content: "✓"; position: absolute; left: 0; top: 0; color: var(--good); font-weight: 900; }
.video-grid { display: grid; grid-template-columns: repeat(3, 1fr); gap: 18px; }
.video-card { border-radius: var(--radius); overflow: hidden; background: var(--paper); border: 1px solid var(--line); box-shadow: var(--shadow); }
.video-frame { position: relative; aspect-ratio: 16 / 9; background: #0f172a; overflow: hidden; }
.video-frame video { width: 100%; height: 100%; object-fit: cover; display: block; }
.play-overlay { position: absolute; inset: 0; display: grid; place-items: center; background: rgba(15,23,42,0.18); opacity: 0; transition: opacity .2s ease; }
.video-card:hover .play-overlay, .video-card:focus-within .play-overlay, .video-card.is-active .play-overlay { opacity: 1; }
.play-overlay span { width: 64px; height: 64px; border-radius: 999px; background: rgba(255,255,255,0.94); display: grid; place-items: center; color: var(--brand-dark); font-weight: 900; box-shadow: 0 10px 22px rgba(15,23,42,.2); }
.video-body { padding: 18px; }
.video-meta { display: flex; flex-wrap: wrap; gap: 8px; color: var(--muted); font-size: 13px; margin-top: 12px; }
.timeline { border-left: 3px solid #bae6fd; padding-left: 18px; }
.timeline article { margin-bottom: 24px; background: white; border: 1px solid var(--line); border-radius: 18px; padding: 18px; }
.review-grid { display: grid; grid-template-columns: repeat(2, 1fr); gap: 18px; }
.review-card { background: #fff; border: 1px solid var(--line); border-radius: var(--radius); padding: 22px; }
.review-card blockquote { margin: 0; color: #334155; }
.review-card cite { display: block; margin-top: 12px; color: var(--muted); font-style: normal; }
.faq-list { display: grid; gap: 12px; }
details { background: #fff; border: 1px solid var(--line); border-radius: 18px; padding: 16px 18px; }
summary { cursor: pointer; font-weight: 800; }
details p { color: var(--muted); }
.cta-panel { background: linear-gradient(135deg, #0f172a, #075985); color: #fff; border-radius: 34px; padding: 36px; display: grid; grid-template-columns: 1.1fr .9fr; gap: 24px; align-items: center; }
.cta-panel p { color: rgba(255,255,255,.78); }
.breadcrumb { color: var(--muted); padding-top: 26px; font-size: 14px; }
.breadcrumb a { color: var(--brand-dark); }
.page-hero { padding: 42px 0 28px; }
.kv-list { display: grid; grid-template-columns: repeat(2, 1fr); gap: 16px; }
.kv-list div { border: 1px solid var(--line); border-radius: 18px; padding: 18px; background: #fff; }
.site-footer { margin-top: 48px; padding: 44px 0; background: #0f172a; color: #e2e8f0; }
.footer-grid { display: grid; grid-template-columns: 1.3fr .7fr 1fr; gap: 28px; }
.footer-brand { display: inline-flex; align-items: center; gap: 10px; font-weight: 900; font-size: 22px; margin-bottom: 12px; }
.footer-logo { width: 112px; filter: brightness(0) invert(1); }
.site-footer a { display: block; color: #bae6fd; margin: 8px 0; }
.site-footer p { color: #cbd5e1; }
.site-footer h2 { font-size: 18px; margin-bottom: 12px; }
@media (max-width: 900px) {
  .header-inner, .hero-grid, .section-heading, .feature-grid, .cta-panel, .footer-grid { grid-template-columns: 1fr; display: grid; }
  .main-nav { justify-content: flex-start; }
  .cards, .video-grid { grid-template-columns: repeat(2, 1fr); }
  .hero-metrics { grid-template-columns: 1fr; }
}
@media (max-width: 640px) {
  .container { width: min(100% - 24px, 1160px); }
  .header-inner { gap: 12px; }
  .search-box { grid-template-columns: 1fr; }
  .cards, .video-grid, .review-grid, .kv-list { grid-template-columns: 1fr; }
  .hero { padding-top: 42px; }
  .section { padding: 42px 0; }
  h1 { font-size: 34px; }
}