:root {
  --green: #173f35;
  --green-2: #245949;
  --green-soft: #dfe9df;
  --cream: #f5efe4;
  --paper: #fffaf1;
  --ink: #24302d;
  --muted: #6e7a74;
  --line: rgba(36, 48, 45, 0.12);
  --shadow: 0 20px 60px rgba(23, 63, 53, 0.12);
  --radius: 28px;
  --radius-sm: 18px;
}
* { box-sizing: border-box; }
html { scroll-behavior: smooth; }
body {
  margin: 0;
  color: var(--ink);
  background: var(--paper);
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", Arial, sans-serif;
  line-height: 1.72;
}
a { color: inherit; text-decoration: none; }
img { max-width: 100%; display: block; }
.container { width: min(1180px, calc(100% - 36px)); margin: 0 auto; }
.narrow { width: min(860px, calc(100% - 36px)); }
.site-header {
  position: sticky;
  top: 0;
  z-index: 50;
  background: rgba(255, 250, 241, 0.88);
  backdrop-filter: blur(18px);
  border-bottom: 1px solid var(--line);
}
.header-inner { min-height: 76px; display: flex; align-items: center; justify-content: space-between; gap: 24px; }
.brand { display: inline-flex; align-items: center; gap: 12px; font-weight: 800; letter-spacing: 0.08em; }
.brand-mark {
  width: 42px;
  height: 42px;
  border-radius: 14px;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  background: var(--green);
  color: var(--cream);
  box-shadow: 0 12px 30px rgba(23, 63, 53, 0.2);
}
.brand-text { font-size: 18px; color: var(--green); }
.site-nav { display: flex; gap: 4px; align-items: center; flex-wrap: wrap; justify-content: flex-end; }
.site-nav a { padding: 9px 12px; border-radius: 999px; color: #3d4b47; font-size: 14px; }
.site-nav a:hover, .site-nav a.active { background: var(--green); color: var(--cream); }
.nav-toggle { display: none; border: 0; background: var(--green); color: var(--cream); width: 42px; height: 42px; border-radius: 14px; font-size: 20px; }
.hero, .page-hero { position: relative; overflow: hidden; }
.hero-home { padding: 84px 0 52px; background: radial-gradient(circle at 75% 20%, #d9ead8 0, rgba(217,234,216,0) 32%), linear-gradient(145deg, #fffaf1 0%, #eef2e7 100%); }
.hero-grid { display: grid; grid-template-columns: 1.02fr 0.98fr; align-items: center; gap: 44px; }
.eyebrow { display: inline-flex; align-items: center; gap: 8px; color: var(--green-2); font-weight: 700; font-size: 14px; letter-spacing: 0.12em; margin-bottom: 14px; }
.eyebrow::before { content: ""; width: 28px; height: 2px; border-radius: 2px; background: currentColor; opacity: 0.65; }
.eyebrow.light { color: var(--cream); }
h1, h2, h3 { line-height: 1.24; margin: 0 0 14px; color: var(--green); }
h1 { font-size: clamp(38px, 6vw, 72px); letter-spacing: -0.06em; }
h2 { font-size: clamp(26px, 3.2vw, 44px); letter-spacing: -0.04em; }
h3 { font-size: 20px; }
p { margin: 0 0 14px; color: var(--muted); }
.lead { font-size: 18px; color: #45524e; max-width: 760px; }
.hero-actions, .hero .btn { margin-top: 18px; }
.btn { display: inline-flex; align-items: center; justify-content: center; min-height: 48px; padding: 0 22px; border-radius: 999px; font-weight: 700; border: 1px solid transparent; cursor: pointer; }
.btn.primary { background: var(--green); color: var(--cream); box-shadow: 0 18px 40px rgba(23, 63, 53, 0.18); }
.btn.ghost { border-color: rgba(23, 63, 53, 0.18); margin-left: 10px; background: rgba(255,255,255,0.45); color: var(--green); }
.btn.light-btn { background: var(--cream); color: var(--green); }
.domain-card { margin-top: 28px; padding: 20px; border: 1px solid var(--line); border-radius: var(--radius-sm); background: rgba(255, 250, 241, 0.72); box-shadow: var(--shadow); max-width: 440px; }
.domain-card span, .domain-card small { display: block; color: var(--muted); }
.domain-card strong { display: block; color: var(--green); font-size: 24px; word-break: break-all; margin: 6px 0; }
.hero-media { position: relative; }
.hero-media img, .rounded-media { border-radius: var(--radius); box-shadow: var(--shadow); }
.section { padding: 86px 0; }
.muted { background: #f1eadf; }
.section-head { text-align: center; max-width: 820px; margin: 0 auto 42px; }
.section-head.compact { text-align: left; margin: 0; }
.three-strip { display: grid; grid-template-columns: repeat(3, 1fr); gap: 18px; }
.three-strip article, .soft-card, .path-card, .value-grid article, .topic-map-grid article, .course-card, .device-grid article {
  padding: 26px;
  border: 1px solid var(--line);
  background: rgba(255,250,241,0.78);
  border-radius: var(--radius-sm);
}
.three-strip span, .tag, .course-card span, .topic-map-grid span { display: inline-flex; color: var(--green-2); font-weight: 700; font-size: 13px; letter-spacing: 0.08em; margin-bottom: 10px; }
.card-grid { display: grid; gap: 22px; }
.card-grid.four { grid-template-columns: repeat(4, 1fr); }
.card-grid.three { grid-template-columns: repeat(3, 1fr); }
.topic-card, .doc-card, .video-card, .audience-grid article {
  background: var(--paper);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  overflow: hidden;
  box-shadow: 0 14px 44px rgba(23, 63, 53, 0.08);
}
.topic-card h3, .topic-card p, .topic-card .tag, .doc-card h2, .doc-card p, .doc-card .tag, .doc-card a { margin-left: 20px; margin-right: 20px; }
.topic-card .tag, .doc-card .tag { margin-top: 20px; }
.doc-card a { display: inline-flex; margin-bottom: 22px; color: var(--green); font-weight: 800; }
.split { display: grid; grid-template-columns: 1fr 1fr; gap: 56px; align-items: center; }
.split.reverse { grid-template-columns: 1fr 1fr; }
.check-list { list-style: none; padding: 0; margin: 22px 0 0; }
.check-list li { position: relative; padding-left: 28px; margin-bottom: 12px; color: #4f5d58; }
.check-list li::before { content: ""; position: absolute; left: 0; top: 10px; width: 12px; height: 12px; border-radius: 50%; background: var(--green-2); }
.text-link { color: var(--green); font-weight: 800; border-bottom: 2px solid rgba(23, 63, 53, 0.3); }
.dark-panel-wrap { background: var(--paper); }
.dark-panel { padding: 48px; border-radius: 36px; background: linear-gradient(135deg, #173f35 0%, #0e2722 100%); color: var(--cream); display: grid; grid-template-columns: 0.9fr 1.1fr; gap: 32px; align-items: center; box-shadow: var(--shadow); }
.dark-panel h2 { color: var(--cream); }
.dark-panel p { color: rgba(245,239,228,0.78); }
.mini-grid { display: grid; grid-template-columns: repeat(3, 1fr); gap: 16px; }
.mini-grid article { background: rgba(255,250,241,0.1); border: 1px solid rgba(255,250,241,0.14); border-radius: 22px; padding: 18px; }
.mini-grid img { height: 92px; object-fit: contain; margin-bottom: 12px; }
.mini-grid strong, .mini-grid span { display: block; }
.mini-grid span { color: rgba(245,239,228,0.72); font-size: 14px; }
.path-grid { display: grid; grid-template-columns: repeat(4, 1fr); gap: 18px; }
.path-card span, .value-grid span { display: inline-flex; width: 48px; height: 48px; border-radius: 50%; background: var(--green); color: var(--cream); align-items: center; justify-content: center; font-weight: 800; margin-bottom: 18px; }
.feature-list { display: grid; gap: 18px; }
.feature-list article { display: grid; grid-template-columns: 250px 1fr; gap: 24px; align-items: center; padding: 18px; border-radius: var(--radius); background: var(--paper); border: 1px solid var(--line); }
.feature-list img { border-radius: 18px; }
.editorial { display: grid; grid-template-columns: 0.9fr 1.1fr; gap: 44px; align-items: center; }
.recommend-list { display: grid; gap: 14px; }
.recommend-list a { padding: 22px; border-radius: 20px; background: #f0eadf; color: var(--green); font-weight: 800; border: 1px solid var(--line); }
.faq-list { display: grid; gap: 14px; }
details { border: 1px solid var(--line); background: var(--paper); border-radius: 18px; padding: 18px 22px; }
summary { cursor: pointer; font-weight: 800; color: var(--green); }
details p { margin-top: 10px; }
.contact-cta { padding-top: 30px; }
.cta-card { padding: 46px; border-radius: 36px; display: flex; justify-content: space-between; gap: 24px; align-items: center; background: linear-gradient(135deg, #245949, #173f35); color: var(--cream); }
.cta-card h2 { color: var(--cream); }
.cta-card p { color: rgba(245,239,228,0.78); }
.page-hero { padding: 94px 0 82px; background: radial-gradient(circle at 20% 10%, rgba(215,231,210,0.95), transparent 34%), linear-gradient(135deg, #fffaf1, #efe8db); text-align: center; }
.documentary-hero, .topics-hero, .learning-hero, .videos-hero, .contact-hero { background: radial-gradient(circle at 80% 12%, rgba(36,89,73,0.18), transparent 32%), linear-gradient(135deg, #fffaf1, #eee7dc); }
.filter-bar { display: flex; flex-wrap: wrap; justify-content: center; gap: 10px; margin-bottom: 28px; }
.filter-btn { border: 1px solid var(--line); background: var(--paper); color: var(--green); border-radius: 999px; padding: 10px 18px; font-weight: 800; cursor: pointer; }
.filter-btn.active, .filter-btn:hover { background: var(--green); color: var(--cream); }
.value-grid, .audience-grid, .topic-map-grid, .device-grid { display: grid; grid-template-columns: repeat(3, 1fr); gap: 22px; }
.audience-grid article { padding: 28px; text-align: center; }
.audience-grid img { width: 120px; height: 120px; margin: 0 auto 18px; }
.topic-map-grid { grid-template-columns: repeat(2, 1fr); }
.course-card ul { padding-left: 20px; margin-bottom: 0; color: #52605c; }
.video-grid { display: grid; grid-template-columns: repeat(2, 1fr); gap: 22px; }
.video-card { padding-bottom: 22px; }
.video-cover { position: relative; }
.video-cover span { position: absolute; left: 20px; bottom: 20px; background: rgba(23,63,53,0.88); color: var(--cream); border-radius: 999px; padding: 8px 16px; font-weight: 800; }
.video-card h2, .video-card p { margin-left: 22px; margin-right: 22px; }
.video-card h2 { margin-top: 22px; }
.contact-grid { display: grid; grid-template-columns: 0.92fr 1.08fr; gap: 36px; align-items: start; }
.contact-info, .contact-form { padding: 32px; border-radius: var(--radius); background: var(--paper); border: 1px solid var(--line); box-shadow: 0 14px 44px rgba(23, 63, 53, 0.08); }
.contact-info h2 { word-break: break-all; }
.info-list { margin-top: 24px; border-top: 1px solid var(--line); padding-top: 20px; }
.contact-form { display: grid; gap: 16px; }
.contact-form label { display: grid; gap: 8px; color: var(--green); font-weight: 800; }
input, select, textarea { width: 100%; border: 1px solid var(--line); border-radius: 16px; padding: 13px 14px; font: inherit; background: #fffdf8; color: var(--ink); }
.site-footer { padding: 56px 0; background: #142f29; color: var(--cream); }
.footer-grid { display: grid; grid-template-columns: 1.3fr 0.7fr 1fr; gap: 30px; }
.footer-brand { font-size: 22px; font-weight: 900; margin-bottom: 12px; }
.site-footer h3 { color: var(--cream); font-size: 16px; }
.site-footer p, .site-footer a { color: rgba(245,239,228,0.74); }
.site-footer a { display: block; margin-bottom: 8px; }
.reveal { opacity: 0; transform: translateY(18px); transition: opacity .75s ease, transform .75s ease; }
.reveal.visible { opacity: 1; transform: translateY(0); }
.delay-one { transition-delay: .12s; }
@media (max-width: 980px) {
  .nav-toggle { display: inline-flex; align-items: center; justify-content: center; }
  .site-nav { position: absolute; left: 18px; right: 18px; top: 76px; display: none; flex-direction: column; align-items: stretch; background: var(--paper); padding: 14px; border: 1px solid var(--line); border-radius: 18px; box-shadow: var(--shadow); }
  .site-nav.open { display: flex; }
  .hero-grid, .split, .split.reverse, .dark-panel, .editorial, .contact-grid { grid-template-columns: 1fr; }
  .card-grid.four, .path-grid { grid-template-columns: repeat(2, 1fr); }
  .three-strip, .card-grid.three, .value-grid, .audience-grid, .device-grid { grid-template-columns: 1fr; }
  .mini-grid, .topic-map-grid, .video-grid { grid-template-columns: 1fr; }
  .feature-list article { grid-template-columns: 1fr; }
  .footer-grid { grid-template-columns: 1fr; }
}
@media (max-width: 620px) {
  .container { width: min(100% - 24px, 1180px); }
  .hero-home, .page-hero { padding: 56px 0 46px; }
  .section { padding: 58px 0; }
  .card-grid.four, .path-grid { grid-template-columns: 1fr; }
  .btn.ghost { margin-left: 0; margin-top: 10px; }
  .hero-actions { display: grid; }
  .dark-panel, .cta-card { padding: 28px; }
  .cta-card { display: grid; }
}