:root {
  --bg: #f7f8fb;
  --surface: #ffffff;
  --text: #1a1f2b;
  --muted: #5a6475;
  --brand: #003087;
  --border: #e2e6ee;
}
@media (prefers-color-scheme: dark) {
  :root {
    --bg: #0f1420;
    --surface: #171e2e;
    --text: #e8ecf4;
    --muted: #9aa5b8;
    --brand: #8fb0ff;
    --border: #273047;
  }
}
* { box-sizing: border-box; }
body {
  margin: 0;
  background: var(--bg);
  color: var(--text);
  font: 16px/1.6 system-ui, -apple-system, "Segoe UI", Roboto, sans-serif;
}
main {
  max-width: 720px;
  margin: 0 auto;
  padding: 48px 16px 64px;
}
h1 { font-size: 2rem; color: var(--brand); line-height: 1.2; margin: 0 0 8px; }
h2 { font-size: 1.3rem; line-height: 1.3; margin: 32px 0 8px; }
p, li { color: var(--text); }
.muted { color: var(--muted); }
.card {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: 12px;
  padding: 20px;
  margin-top: 24px;
}
a { color: var(--brand); }
nav { display: flex; gap: 16px; flex-wrap: wrap; margin-top: 24px; }
footer { margin-top: 48px; font-size: 0.9rem; color: var(--muted); }