:root{
  --bg:#f6f7f9;--surface:#fff;--ink:#1c2230;--ink-2:#4a5368;--line:#e2e5ec;--accent:#0f766e;--accent-ink:#0b5a54;
}
@media (prefers-color-scheme: dark){
  :root{--bg:#12151c;--surface:#1a1f2a;--ink:#eef0f5;--ink-2:#aab1c2;--line:#2a3140;--accent:#2dd4bf;--accent-ink:#5eead4;}
}
*{box-sizing:border-box;}
html{-webkit-text-size-adjust:100%;}
body{margin:0;background:var(--bg);color:var(--ink);font:16px/1.65 -apple-system,BlinkMacSystemFont,"Segoe UI","PingFang SC","Noto Sans SC","Microsoft YaHei",Roboto,sans-serif;}
a{color:var(--accent-ink);}
header,main,footer{max-width:820px;margin:0 auto;padding:0 20px;}
header{display:flex;flex-wrap:wrap;align-items:center;justify-content:space-between;gap:12px;padding-top:22px;padding-bottom:18px;}
.brand{font-weight:700;letter-spacing:.02em;color:var(--ink);text-decoration:none;}
nav{display:flex;flex-wrap:wrap;gap:16px;font-size:14.5px;}
nav a{text-decoration:none;color:var(--ink-2);}
nav a:hover,nav a[aria-current]{color:var(--accent-ink);}
main{padding-bottom:40px;}
.card{background:var(--surface);border:1px solid var(--line);border-radius:14px;padding:26px 28px;margin:0 0 18px;}
h1{font-size:30px;line-height:1.25;margin:6px 0 10px;}
h2{font-size:19px;margin:26px 0 8px;}
h3{font-size:16px;margin:18px 0 6px;}
p,li{color:var(--ink);}
.lede{color:var(--ink-2);font-size:17px;}
.muted{color:var(--ink-2);font-size:14px;}
ul{padding-left:22px;margin:8px 0;}
li{margin:4px 0;}
dl{margin:10px 0 0;display:grid;grid-template-columns:110px 1fr;gap:8px 16px;}
dt{color:var(--ink-2);}
dd{margin:0;}
hr{border:0;border-top:1px solid var(--line);margin:30px 0;}
footer{padding-top:8px;padding-bottom:40px;color:var(--ink-2);font-size:13.5px;}
footer a{color:var(--ink-2);}
@media (max-width:560px){
  .card{padding:20px 18px;}
  h1{font-size:25px;}
  dl{grid-template-columns:1fr;gap:2px 0;}
  dd{margin-bottom:10px;}
}