:root {
  --bg: #ffffff;
  --fg: #1a1f2b;
  --muted: #4a5468;
  --accent: #003b8e;
  --line: #dde3ec;
  --box: #f4f7fb;
}
@media (prefers-color-scheme: dark) {
  :root {
    --bg: #0f141d;
    --fg: #e7ecf3;
    --muted: #aab4c4;
    --accent: #8db8ff;
    --line: #2a3446;
    --box: #172030;
  }
}
* { box-sizing: border-box; }
html { -webkit-text-size-adjust: 100%; }
body {
  margin: 0;
  background: var(--bg);
  color: var(--fg);
  font: 17px/1.6 system-ui, -apple-system, "Segoe UI", Roboto, Arial, sans-serif;
}
header, main, footer { max-width: 760px; margin: 0 auto; padding: 0 16px; }
header { padding-top: 28px; padding-bottom: 12px; border-bottom: 1px solid var(--line); }
header a.brand { color: var(--fg); font-weight: 700; font-size: 1.15rem; text-decoration: none; }
nav { margin-top: 6px; }
nav a { margin-right: 18px; }
main { padding-top: 24px; padding-bottom: 40px; }
h1 { font-size: 1.9rem; line-height: 1.25; margin: 0 0 12px; }
h2 { font-size: 1.25rem; margin: 32px 0 8px; }
p, li { color: var(--fg); }
.lead { font-size: 1.1rem; color: var(--muted); }
.box { background: var(--box); border: 1px solid var(--line); border-radius: 8px; padding: 14px 18px; margin: 20px 0; }
code { overflow-wrap: anywhere; font-size: 0.92em; }
a { color: var(--accent); }
a:focus-visible { outline: 3px solid var(--accent); outline-offset: 2px; }
footer { padding-top: 16px; padding-bottom: 32px; border-top: 1px solid var(--line); color: var(--muted); font-size: 0.95rem; }
footer a { margin-right: 16px; }