:root {
  --bg: #ffffff;
  --fg: #1c1c1e;
  --muted: #6e6e73;
  --accent: #0071e3;
  --border: #e5e5ea;
}
@media (prefers-color-scheme: dark) {
  :root { --bg: #000; --fg: #f5f5f7; --muted: #8e8e93; --border: #2c2c2e; }
}
* { box-sizing: border-box; }
html, body {
  margin: 0;
  padding: 0;
  background: var(--bg);
  color: var(--fg);
  font-family: -apple-system, BlinkMacSystemFont, "SF Pro Text", "Helvetica Neue", Helvetica, Arial, "PingFang SC", sans-serif;
  font-size: 17px;
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
}
.wrap {
  max-width: 720px;
  margin: 0 auto;
  padding: 48px 24px 96px;
}
header h1 {
  font-size: 32px;
  font-weight: 700;
  letter-spacing: -0.02em;
  margin: 0 0 8px;
}
.sub { color: var(--muted); margin: 0 0 32px; }
nav.links { display: flex; flex-direction: column; gap: 12px; margin-top: 24px; }
nav.links a {
  display: block;
  padding: 16px 20px;
  background: transparent;
  border: 1px solid var(--border);
  border-radius: 12px;
  color: var(--fg);
  text-decoration: none;
  font-weight: 500;
  transition: background 0.15s;
}
nav.links a:hover { background: rgba(127,127,127,0.08); }
h1.doc-title { font-size: 28px; margin-bottom: 4px; }
h2 { font-size: 20px; font-weight: 600; margin-top: 32px; margin-bottom: 8px; letter-spacing: -0.01em; }
h3 { font-size: 17px; font-weight: 600; margin-top: 20px; margin-bottom: 4px; }
p, li { color: var(--fg); }
.meta { color: var(--muted); font-size: 14px; margin-bottom: 24px; }
a { color: var(--accent); }
hr { border: 0; border-top: 1px solid var(--border); margin: 40px 0; }
.back { display: inline-block; margin-bottom: 24px; color: var(--muted); text-decoration: none; font-size: 14px; }
.back:hover { color: var(--accent); }
footer { margin-top: 64px; color: var(--muted); font-size: 13px; }
ul { padding-left: 20px; }
li { margin-bottom: 4px; }