:root {
  color-scheme: light;
  --bg: #fff;
  --surface: #f5f5f7;
  --fg: #1d1d1f;
  --muted: #62626a;
  --line: #e8e8ed;
  --accent: #006bd6;
}
:root[data-theme="dark"] {
  color-scheme: dark;
  --bg: #1c1c1e;
  --surface: #242426;
  --fg: #f5f5f7;
  --muted: #b9b9bf;
  --line: #38383d;
  --accent: #79baff;
}
* { box-sizing: border-box; }
html { scroll-behavior: smooth; }
body {
  min-width: 320px;
  margin: 0;
  color: var(--fg);
  background: var(--bg);
  font: 16px/1.85 -apple-system, BlinkMacSystemFont, "PingFang SC", "Microsoft YaHei", sans-serif;
}
a { color: var(--accent); text-underline-offset: 3px; }
a:focus-visible { outline: 2px solid var(--accent); outline-offset: 4px; }
.skip { position: absolute; left: -9999px; }
.skip:focus { left: 16px; top: 10px; z-index: 3; background: var(--bg); padding: 8px 14px; }
.container { width: min(760px, calc(100% - 40px)); margin: auto; }
.topbar { border-bottom: 1px solid var(--line); }
.topbar .container { min-height: 74px; display: flex; align-items: center; justify-content: space-between; gap: 24px; }
.brand { display: inline-flex; align-items: center; color: var(--fg); font-size: 21px; font-weight: 700; white-space: nowrap; text-decoration: none; }
.brandmark { flex: none; margin-right: 8px; }
.brand span { color: var(--accent); }
.topnav { display: flex; flex-wrap: wrap; justify-content: flex-end; gap: 8px 20px; font-size: 13px; }
.topnav a { color: var(--muted); text-decoration: none; }
.topnav a:hover, .topnav a[aria-current="page"] { color: var(--accent); }
main { padding-top: 35px; padding-bottom: 90px; }
.breadcrumb { font-size: 13px; color: var(--muted); margin-bottom: 45px; }
.breadcrumb a { color: inherit; }
.eyebrow { font-size: 12px; color: var(--accent); letter-spacing: .11em; font-weight: 700; }
h1, h2 { letter-spacing: -.035em; line-height: 1.35; }
h1 { margin: 14px 0 18px; font-size: clamp(32px, 5vw, 48px); }
.lead { font-size: 19px; line-height: 1.8; color: var(--muted); }
.article-body { margin-top: 60px; }
.article-body section { margin-top: 42px; }
h2 { margin: 0 0 16px; font-size: 25px; }
p { margin: 0 0 18px; }
ol, ul { padding-left: 1.5em; }
li + li { margin-top: 10px; }
.note { background: var(--surface); border-left: 3px solid var(--accent); padding: 18px 20px; border-radius: 0 10px 10px 0; }
.note p:last-child { margin-bottom: 0; }
.related { border-top: 1px solid var(--line); margin-top: 64px; padding-top: 26px; }
.related h2 { font-size: 18px; }
.related ul { list-style: none; display: flex; flex-wrap: wrap; gap: 8px 22px; padding: 0; }
.related li { margin: 0; }
.footer { border-top: 1px solid var(--line); padding: 30px 0 48px; color: var(--muted); font-size: 12px; }
.footer a { color: inherit; }
.footer .record { white-space: nowrap; }
@media (max-width: 600px) {
  .topbar .container { align-items: flex-start; flex-direction: column; gap: 8px; padding: 16px 0; }
  .topnav { justify-content: flex-start; }
  main { padding-top: 24px; padding-bottom: 60px; }
  .breadcrumb { margin-bottom: 30px; }
  .lead { font-size: 17px; }
}
@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
}