:root {
  color-scheme: light dark;
  --background: #f7f7f5;
  --surface: #ffffff;
  --text: #202326;
  --secondary: #525960;
  --line: #d8dcdf;
  --accent: #215a91;
  --focus: #215a91;
  --space-small: 0.75rem;
  --space-medium: 1.5rem;
  --space-large: 2.5rem;
}
@media (prefers-color-scheme: dark) {
  :root {
    --background: #191b1d;
    --surface: #222528;
    --text: #f0f1f2;
    --secondary: #b9c0c7;
    --line: #464c52;
    --accent: #9fc9f2;
    --focus: #9fc9f2;
  }
}
* { box-sizing: border-box; }
html { font-size: 100%; }
body {
  margin: 0;
  color: var(--text);
  background: var(--background);
  font-family: "Segoe UI", "Microsoft YaHei UI", system-ui, sans-serif;
  font-size: 1rem;
  line-height: 1.7;
}
a { color: var(--accent); text-underline-offset: 0.2em; }
a:hover { text-decoration-thickness: 0.14em; }
a:focus-visible { outline: 3px solid var(--focus); outline-offset: 4px; border-radius: 2px; }
.skip-link { position: absolute; left: 1rem; top: -6rem; padding: 0.6rem 1rem; background: var(--surface); z-index: 1; }
.skip-link:focus { top: 0.5rem; }
.site-header, main, .site-footer { width: min(100% - 3rem, 56rem); margin-inline: auto; }
.site-header { padding-block: 1.5rem; display: flex; flex-wrap: wrap; align-items: center; justify-content: space-between; gap: 1rem 2rem; border-bottom: 1px solid var(--line); }
.brand { color: var(--text); font-size: 1.15rem; font-weight: 650; text-decoration: none; }
nav { display: flex; flex-wrap: wrap; gap: 0.35rem 1.25rem; }
nav a { padding-block: 0.25rem; }
nav a[aria-current="page"] { color: var(--text); font-weight: 650; }
main { padding-block: var(--space-large); overflow-wrap: anywhere; }
.eyebrow { color: var(--secondary); font-size: 0.875rem; margin: 0 0 var(--space-small); }
h1 { font-size: clamp(1.8rem, 4vw, 2.5rem); line-height: 1.2; letter-spacing: -0.025em; margin: 0 0 1rem; font-weight: 650; }
h2 { font-size: 1.3rem; line-height: 1.35; margin: 0 0 0.75rem; font-weight: 650; }
p { margin: 0 0 1rem; max-width: 76ch; }
.lead { font-size: 1.15rem; line-height: 1.65; max-width: 65ch; }
.muted { color: var(--secondary); }
.notice { background: var(--surface); border-left: 3px solid var(--line); padding: 1rem 1.25rem; margin: var(--space-medium) 0; }
.notice p:last-child, section p:last-child { margin-bottom: 0; }
section { padding-top: 1.75rem; margin-top: 1.75rem; border-top: 1px solid var(--line); }
ul, ol { padding-left: 1.35rem; margin: 0.75rem 0 1rem; }
li { padding-left: 0.25rem; margin-block: 0.4rem; }
code { font-family: ui-monospace, Consolas, monospace; font-size: 0.9em; overflow-wrap: anywhere; }
.table-wrap { overflow-x: auto; margin-block: 1rem; }
table { width: 100%; border-collapse: collapse; min-width: 30rem; text-align: left; }
caption { text-align: left; color: var(--secondary); margin-bottom: 0.5rem; }
th, td { padding: 0.75rem; border-bottom: 1px solid var(--line); vertical-align: top; }
th { background: var(--surface); font-weight: 650; }
.site-footer { border-top: 1px solid var(--line); padding-block: 1.5rem 2rem; font-size: 0.875rem; color: var(--secondary); }
.site-footer p { margin-bottom: 0.5rem; }
@media (max-width: 36rem) {
  .site-header, main, .site-footer { width: calc(100% - 2rem); }
  .site-header { align-items: flex-start; flex-direction: column; gap: 0.5rem; }
  main { padding-block: 1.75rem; }
  .lead { font-size: 1.05rem; }
}
@media print {
  :root { color-scheme: light; --background: #fff; --surface: #fff; --text: #000; --secondary: #333; --line: #aaa; --accent: #000; }
  .skip-link, nav { display: none; }
  .site-header, main, .site-footer { width: 100%; }
  a { color: inherit; }
  h2 { break-after: avoid; }
  tr { break-inside: avoid; }
}