:root {
  --paper: #ffffff;
  --panel: #f2f5f8;
  --ink: #18212e;
  --muted: #5a6575;
  --line: #d8dee6;
  --seal: #b8342a;
  --link: #1d4f86;
  color-scheme: light;
}
@media (prefers-color-scheme: dark) {
  :root {
    --paper: #12161c;
    --panel: #1a2029;
    --ink: #e7ebf0;
    --muted: #9aa5b3;
    --line: #2c3440;
    --seal: #d9564a;
    --link: #8fb8e8;
    color-scheme: dark;
  }
}
* { box-sizing: border-box; }
html { -webkit-text-size-adjust: 100%; }
body {
  margin: 0;
  background: var(--paper);
  color: var(--ink);
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", "Helvetica Neue", Arial, "PingFang SC", "Microsoft YaHei", sans-serif;
  font-size: 17px;
  line-height: 1.6;
}
a { color: var(--link); text-underline-offset: 3px; }
a:focus-visible { outline: 2px solid var(--link); outline-offset: 3px; border-radius: 2px; }
.wrap { max-width: 860px; margin: 0 auto; padding: 0 24px; }

/* 页眉 */
.top { border-bottom: 1px solid var(--line); }
.top .wrap { display: flex; align-items: center; justify-content: space-between; min-height: 64px; gap: 16px; }
.brand { display: flex; align-items: center; gap: 12px; color: var(--ink); text-decoration: none; font-weight: 600; }
.top nav { display: flex; gap: 20px; font-size: 15px; }
.top nav a { color: var(--muted); text-decoration: none; }
.top nav a:hover { color: var(--ink); }

/* 印章：页面唯一的装饰元素 */
.seal {
  display: inline-grid;
  place-items: center;
  border: 2px solid var(--seal);
  color: var(--seal);
  font-family: "Songti SC", "STSong", "SimSun", "Noto Serif SC", serif;
  font-weight: 700;
  line-height: 1;
  writing-mode: vertical-rl;
  letter-spacing: 0.05em;
}
.seal-sm { width: 34px; height: 34px; font-size: 13px; border-radius: 3px; }
.seal-lg { width: 112px; height: 112px; font-size: 44px; border-width: 3px; border-radius: 6px; }

/* 首屏 */
.hero { padding: 72px 0 56px; display: grid; grid-template-columns: auto 1fr; gap: 36px; align-items: center; }
.hero h1 { margin: 0; font-size: clamp(28px, 4.2vw, 40px); line-height: 1.2; font-weight: 700; letter-spacing: -0.01em; }
.hero .cn { margin: 10px 0 0; font-size: 20px; color: var(--muted); }
.hero .lead { margin: 20px 0 0; max-width: 34em; }

section { padding: 48px 0; border-top: 1px solid var(--line); }
h2 { margin: 0 0 24px; font-size: 24px; line-height: 1.3; }

/* 产品 */
.apps { display: grid; grid-template-columns: 1fr 1fr; gap: 32px; }
.app h3 { margin: 0 0 6px; font-size: 20px; }
.app p { margin: 0 0 10px; color: var(--muted); }

/* 公司信息 */
dl.facts { margin: 0; display: grid; grid-template-columns: 13em 1fr; background: var(--panel); border-radius: 8px; padding: 8px 24px; }
dl.facts dt, dl.facts dd { padding: 14px 0; border-bottom: 1px solid var(--line); margin: 0; }
dl.facts dt { color: var(--muted); padding-right: 16px; }
dl.facts dt:last-of-type, dl.facts dd:last-of-type { border-bottom: 0; }

/* 文档页 */
.doc { padding: 56px 0 24px; max-width: 42em; }
.doc h1 { margin: 0 0 8px; font-size: 34px; line-height: 1.2; }
.doc .updated { color: var(--muted); margin: 0 0 32px; }
.doc h2 { margin: 36px 0 12px; font-size: 21px; }
.doc p, .doc li { margin: 0 0 12px; }

footer { border-top: 1px solid var(--line); margin-top: 24px; padding: 28px 0 40px; color: var(--muted); font-size: 14px; }
footer .wrap { display: flex; flex-wrap: wrap; justify-content: space-between; gap: 12px; }
footer nav { display: flex; flex-wrap: wrap; gap: 8px 20px; }

@media (max-width: 640px) {
  body { font-size: 16px; }
  .top nav { gap: 14px; font-size: 14px; }
  .hero { grid-template-columns: 1fr; padding: 48px 0 40px; gap: 24px; }
  .seal-lg { width: 88px; height: 88px; font-size: 34px; }
  .apps { grid-template-columns: 1fr; }
  dl.facts { grid-template-columns: 1fr; padding: 4px 18px; }
  dl.facts dt { border-bottom: 0; padding-bottom: 0; }
}