:root {
  color-scheme: light dark;
  --bg: #f4f3fb;
  --card: #ffffff;
  --ink: #201d3a;
  --ink-soft: #6b6796;
  --accent: #5b53d6;
  --line: #e7e4f4;
  --tip-bg: #eef6ec;
  --tip-line: #cfe6c8;
}
@media (prefers-color-scheme: dark) {
  :root {
    --bg: #0b0a14;
    --card: #16131f;
    --ink: #ecebf7;
    --ink-soft: #9a95c4;
    --accent: #a9a2ff;
    --line: #2a2740;
    --tip-bg: #12261a;
    --tip-line: #24502f;
  }
}
* { box-sizing: border-box; }
body {
  margin: 0;
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
  background: var(--bg);
  color: var(--ink);
  line-height: 1.65;
  -webkit-font-smoothing: antialiased;
}
.wrap { max-width: 720px; margin: 0 auto; padding: 48px 24px 80px; }
header.site { text-align: center; margin-bottom: 40px; }
header.site .icon { width: 92px; height: 92px; border-radius: 22.5%; box-shadow: 0 12px 34px -10px rgba(20, 16, 60, .45); display: block; margin: 0 auto 18px; }
header.site .logo { font-size: 2.1rem; font-weight: 800; letter-spacing: -0.5px; }
header.site .tag { color: var(--ink-soft); margin-top: 4px; }
h1 { font-size: 1.8rem; font-weight: 800; letter-spacing: -0.4px; margin: 0 0 4px; }
h2 { font-size: 1.2rem; font-weight: 700; margin: 32px 0 8px; }
.updated { color: var(--ink-soft); font-size: 0.9rem; margin-bottom: 28px; }
p, li { color: var(--ink); }
a { color: var(--accent); text-decoration: none; }
a:hover { text-decoration: underline; }
.card { background: var(--card); border: 1px solid var(--line); border-radius: 16px; padding: 22px 24px; margin: 14px 0; }
.tip { background: var(--tip-bg); border: 1px solid var(--tip-line); border-radius: 16px; padding: 18px 22px; margin: 18px 0; }
.nav { display: flex; flex-wrap: wrap; gap: 12px; justify-content: center; margin-top: 18px; }
.nav a { background: var(--card); border: 1px solid var(--line); border-radius: 999px; padding: 9px 18px; font-weight: 600; color: var(--ink); }
.nav a:hover { border-color: var(--accent); text-decoration: none; }
.back { display: inline-block; margin-bottom: 24px; font-weight: 600; }
footer { text-align: center; color: var(--ink-soft); font-size: 0.85rem; margin-top: 56px; }
code { background: var(--card); border: 1px solid var(--line); padding: 1px 6px; border-radius: 6px; font-size: 0.9em; }
h3 { font-size: 1.05rem; font-weight: 700; margin: 22px 0 4px; }
.lead { color: var(--ink-soft); margin-top: 2px; }
.toc { columns: 2; column-gap: 26px; margin: 10px 0 4px; }
.toc a { display: block; padding: 4px 0; font-weight: 600; break-inside: avoid; }
@media (max-width: 560px) { .toc { columns: 1; } }
section { scroll-margin-top: 20px; }
section + section { border-top: 1px solid var(--line); margin-top: 8px; padding-top: 4px; }