:root {
  color-scheme: light;
  --bg: #eef4fb;
  --ink: #172033;
  --muted: #667085;
  --brand: #0d4e9a;
  --brand-dark: #092f63;
  --accent: #d8a13a;
  --accent-soft: #fff2cf;
  --card: rgba(255, 255, 255, 0.88);
  --line: rgba(15, 33, 67, 0.1);
  --shadow: 0 24px 70px rgba(20, 47, 91, 0.16);
  font-family: "Microsoft YaHei", "PingFang SC", "Noto Sans CJK SC", system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
}
* { box-sizing: border-box; }
html { scroll-behavior: smooth; }
body {
  margin: 0;
  min-height: 100vh;
  color: var(--ink);
  background: radial-gradient(circle at 8% 8%, rgba(77, 142, 221, 0.22), transparent 30rem), radial-gradient(circle at 90% 10%, rgba(216, 161, 58, 0.18), transparent 28rem), linear-gradient(180deg, #f6f9fd 0%, var(--bg) 42%, #f8fafc 100%);
}
a { color: inherit; }
button, input { font: inherit; }
.page-shell { width: min(1200px, calc(100% - 36px)); margin: 0 auto; padding-bottom: 56px; }
.hero {
  position: relative; overflow: hidden; margin-top: 22px; padding: 28px; border-radius: 34px; color: #fff;
  background: linear-gradient(135deg, rgba(9,47,99,0.98), rgba(13,78,154,0.94)), radial-gradient(circle at top right, rgba(255,255,255,0.28), transparent 20rem);
  box-shadow: var(--shadow);
}
.hero::after { content: ""; position: absolute; inset: auto -90px -150px auto; width: 440px; height: 440px; border-radius: 999px; background: rgba(255, 255, 255, 0.08); }
.topbar { display: flex; align-items: center; gap: 14px; position: relative; z-index: 1; }
.brand-mark { display: grid; place-items: center; width: 54px; height: 54px; border-radius: 18px; background: linear-gradient(135deg, #fff, #d7e7ff); color: var(--brand-dark); font-weight: 900; letter-spacing: -0.08em; }
.eyebrow, .section-kicker { margin: 0 0 4px; text-transform: uppercase; letter-spacing: 0.16em; font-size: 12px; opacity: 0.74; }
.topbar strong { font-size: 19px; }
.hero-grid { display: grid; grid-template-columns: minmax(0, 1fr) 340px; gap: 34px; align-items: end; padding: 74px 0 18px; position: relative; z-index: 1; }
.hero-copy h1 { margin: 18px 0 14px; font-size: clamp(40px, 6vw, 76px); line-height: 0.98; letter-spacing: -0.06em; }
.hero-copy p { max-width: 680px; margin: 0; color: rgba(255,255,255,0.78); font-size: 18px; line-height: 1.8; }
.pill { display: inline-flex; padding: 8px 14px; border-radius: 999px; background: rgba(255,255,255,0.14); border: 1px solid rgba(255,255,255,0.22); backdrop-filter: blur(10px); }
.hero-actions { display: flex; flex-wrap: wrap; gap: 14px; margin-top: 32px; }
.primary-action, .secondary-action { display: inline-flex; align-items: center; justify-content: center; min-height: 46px; padding: 0 20px; border-radius: 999px; text-decoration: none; font-weight: 700; }
.primary-action { background: #fff; color: var(--brand-dark); }
.secondary-action { border: 1px solid rgba(255,255,255,0.32); color: #fff; }
.hero-card { position: relative; overflow: hidden; padding: 26px; border-radius: 28px; background: rgba(255,255,255,0.14); border: 1px solid rgba(255,255,255,0.26); backdrop-filter: blur(16px); }
.hero-card-glow { position: absolute; inset: -80px -80px auto auto; width: 180px; height: 180px; background: rgba(216,161,58,0.75); filter: blur(40px); }
.hero-card p, .hero-card span { position: relative; margin: 0; color: rgba(255,255,255,0.74); line-height: 1.7; }
.hero-card strong { position: relative; display: block; margin: 8px 0; font-size: 76px; line-height: 1; letter-spacing: -0.08em; }
.stats { display: grid; grid-template-columns: repeat(4, 1fr); gap: 16px; margin: 22px 0; }
.stats article, .guide, .video-card, .search-box { background: var(--card); border: 1px solid var(--line); box-shadow: 0 14px 44px rgba(20,47,91,0.08); backdrop-filter: blur(12px); }
.stats article { padding: 22px; border-radius: 24px; }
.stats span { display: block; color: var(--brand); font-size: 32px; font-weight: 900; letter-spacing: -0.04em; }
.stats p { margin: 6px 0 0; color: var(--muted); }
.guide { display: grid; grid-template-columns: 0.8fr 1.2fr; gap: 24px; align-items: start; margin: 28px 0 44px; padding: 28px; border-radius: 28px; }
.guide h2, .section-heading h2 { margin: 0; font-size: clamp(26px, 3vw, 38px); letter-spacing: -0.04em; }
.guide .section-kicker, .library .section-kicker { color: var(--brand); opacity: 1; }
.guide ol { margin: 0; padding-left: 22px; color: #475467; line-height: 1.9; }
.section-heading { display: flex; align-items: end; justify-content: space-between; gap: 18px; margin-bottom: 18px; }
.search-box { display: flex; align-items: center; gap: 10px; width: min(420px, 100%); padding: 10px 14px; border-radius: 18px; }
.search-box span { color: var(--brand); font-weight: 800; }
.search-box input { width: 100%; border: 0; outline: 0; background: transparent; color: var(--ink); }
.filters { display: flex; flex-wrap: wrap; gap: 10px; margin-bottom: 14px; }
.filter-chip { border: 1px solid var(--line); background: rgba(255,255,255,0.82); color: #344054; border-radius: 999px; padding: 10px 15px; cursor: pointer; transition: 0.2s ease; }
.filter-chip:hover, .filter-chip.active { background: var(--brand); color: #fff; border-color: var(--brand); transform: translateY(-1px); }
.result-line { margin: 8px 0 18px; color: var(--muted); }
.video-grid { display: grid; grid-template-columns: repeat(3, minmax(0, 1fr)); gap: 18px; }
.video-card { overflow: hidden; border-radius: 26px; transition: transform .2s ease, box-shadow .2s ease; }
.video-card:hover { transform: translateY(-4px); box-shadow: 0 24px 70px rgba(20,47,91,0.16); }
.thumb { position: relative; display: grid; place-items: center; width: 100%; aspect-ratio: 16/9; border: 0; cursor: pointer; color: #fff; background: radial-gradient(circle at 26% 26%, rgba(255,255,255,.3), transparent 12rem), linear-gradient(135deg, #0d4e9a, #173c72 58%, #d8a13a); }
.thumb::after { content: ""; position: absolute; inset: 0; background-image: linear-gradient(135deg, rgba(255,255,255,.12) 25%, transparent 25%, transparent 50%, rgba(255,255,255,.12) 50%, rgba(255,255,255,.12) 75%, transparent 75%); background-size: 32px 32px; opacity: .15; }
.play-icon { position: relative; z-index: 1; width: 62px; height: 62px; border-radius: 999px; background: rgba(255,255,255,.92); box-shadow: 0 14px 34px rgba(0,0,0,.18); }
.play-icon::after { content: ""; position: absolute; left: 25px; top: 19px; border-left: 18px solid var(--brand); border-top: 12px solid transparent; border-bottom: 12px solid transparent; }
.thumb-index { position: absolute; left: 16px; bottom: 14px; z-index: 1; font-weight: 900; opacity: .92; }
.card-body { padding: 18px; }
.card-row { display: flex; align-items: center; gap: 8px; flex-wrap: wrap; }
.dept-badge, .format-badge { display: inline-flex; align-items: center; border-radius: 999px; padding: 5px 9px; font-size: 12px; font-weight: 800; }
.dept-badge { color: var(--brand-dark); background: #e7f0ff; }
.format-badge { color: #8a5a00; background: var(--accent-soft); }
.video-card h3 { min-height: 54px; margin: 12px 0 10px; font-size: 18px; line-height: 1.5; }
.video-card p { min-height: 46px; margin: 0; color: var(--muted); line-height: 1.6; font-size: 14px; }
.card-footer { display: flex; align-items: center; justify-content: space-between; gap: 12px; margin-top: 16px; color: var(--muted); }
.text-play { border: 0; color: var(--brand); background: transparent; font-weight: 900; cursor: pointer; }
.player-dialog { width: min(980px, calc(100% - 28px)); border: 0; padding: 0; border-radius: 28px; background: transparent; }
.player-dialog::backdrop { background: rgba(6, 18, 38, .72); backdrop-filter: blur(8px); }
.dialog-inner { position: relative; padding: 22px; background: #fff; border-radius: 28px; box-shadow: 0 30px 90px rgba(0,0,0,.35); }
.close-dialog { position: absolute; right: 16px; top: 14px; width: 40px; height: 40px; border: 0; border-radius: 999px; background: #f2f4f7; color: #344054; font-size: 26px; cursor: pointer; }
.player-meta { padding-right: 48px; }
.player-meta span { display: inline-flex; margin-bottom: 8px; padding: 5px 10px; border-radius: 999px; color: var(--brand-dark); background: #e7f0ff; font-weight: 900; }
.player-meta h3 { margin: 0; font-size: 24px; }
.player-meta p { margin: 8px 0 18px; color: var(--muted); }
video { display: block; width: 100%; max-height: 68vh; border-radius: 18px; background: #0b1220; }
.dialog-actions { display: flex; justify-content: flex-end; gap: 12px; margin-top: 16px; }
.dialog-actions a, .dialog-actions button { border: 1px solid var(--line); border-radius: 999px; padding: 10px 15px; background: #fff; color: var(--brand); text-decoration: none; font-weight: 900; cursor: pointer; }
.empty-state { grid-column: 1 / -1; padding: 48px; text-align: center; color: var(--muted); background: rgba(255,255,255,.72); border: 1px dashed var(--line); border-radius: 24px; }
.site-footer { margin: 34px 0 0; padding: 18px 0 4px; text-align: center; color: rgba(102,112,133,.82); font-size: 12px; letter-spacing: .04em; }
@media (max-width: 920px) { .page-shell { width: min(100% - 24px, 760px); } .hero-grid, .guide { grid-template-columns: 1fr; } .hero-card { max-width: 420px; } .stats { grid-template-columns: repeat(2, 1fr); } .section-heading { align-items: stretch; flex-direction: column; } .video-grid { grid-template-columns: repeat(2, minmax(0, 1fr)); } }
@media (max-width: 620px) { .hero { padding: 20px; border-radius: 24px; } .hero-grid { padding-top: 48px; } .hero-copy h1 { font-size: 42px; } .stats, .video-grid { grid-template-columns: 1fr; } .guide { padding: 22px; } .dialog-inner { padding: 16px; border-radius: 22px; } }