:root { color-scheme: dark; --bg: #050505; --panel: #0a0a0a; --line: #1a1a1a; --ink: #e8e8e8; --ink-2: #b4b4b4; --ink-3: #888; --brand: #ff9d29;
  --font-sans: "IBM Plex Sans", "Noto Sans SC", "PingFang SC", system-ui, sans-serif; --font-mono: "IBM Plex Mono", "Noto Sans SC", ui-monospace, monospace; }
body { margin: 0; background: var(--bg); color: var(--ink-2); font: 15px/1.75 var(--font-sans); }
header { position: sticky; top: 0; display: flex; align-items: center; gap: 18px; flex-wrap: wrap; padding: 12px 16px; background: rgba(5, 5, 5, 0.92); border-bottom: 1px solid var(--line); }
.brand { display: flex; align-items: center; gap: 8px; color: var(--ink); text-decoration: none; font: 600 12.5px/1 var(--font-mono); letter-spacing: 0.08em; }
nav { display: flex; gap: 14px; flex-wrap: wrap; }
nav a, .back { color: var(--brand); text-decoration: none; font-size: 13.5px; }
main { max-width: 720px; margin: 0 auto; padding: 18px 16px 60px; }
section { padding: 8px 0 18px; border-bottom: 1px solid var(--line); scroll-margin-top: 70px; }
@media (max-width: 520px) { section { scroll-margin-top: 124px; } }   /* 手机上标签换成两行，顶栏比较高 */
h2 { color: var(--ink); font-size: 22px; margin: 18px 0 4px; }
h3 { color: var(--ink); font-size: 15.5px; margin: 18px 0 4px; }
.muted { color: var(--ink-3); font-size: 13px; }
b { color: var(--ink); }
a:focus-visible { outline: 2px solid var(--brand); outline-offset: 2px; }