:root {
  --bg: #ffffff;
  --surface: #f5f6f8;
  --text: #1c1f24;
  --muted: #5b6270;
  --accent: #1a5fb4;
  --border: #dfe2e7;
}
@media (prefers-color-scheme: dark) {
  :root {
    --bg: #15171b;
    --surface: #1e2127;
    --text: #e8eaed;
    --muted: #a3a9b4;
    --accent: #7fb0f0;
    --border: #2e323a;
  }
}
* { box-sizing: border-box; }
body {
  margin: 0;
  background: var(--bg);
  color: var(--text);
  font: 16px/1.65 system-ui, -apple-system, "Segoe UI", Roboto, sans-serif;
}
header, main, footer {
  max-width: 760px;
  margin: 0 auto;
  padding: 0 16px;
}
header {
  display: flex;
  flex-wrap: wrap;
  gap: 8px 24px;
  align-items: center;
  justify-content: space-between;
  padding-top: 24px;
  padding-bottom: 16px;
  border-bottom: 1px solid var(--border);
}
.brand { font-weight: 700; font-size: 1.1rem; color: var(--text); text-decoration: none; }
nav { display: flex; flex-wrap: wrap; gap: 16px; font-size: .95rem; }
a { color: var(--accent); }
main { padding-top: 32px; padding-bottom: 48px; }
h1 { font-size: 1.9rem; line-height: 1.25; margin: 0 0 8px; }
h2 { font-size: 1.25rem; margin: 36px 0 8px; }
h3 { font-size: 1.05rem; margin: 24px 0 4px; }
.lead { font-size: 1.1rem; color: var(--muted); margin-top: 0; }
.meta { color: var(--muted); font-size: .9rem; }
.box {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: 8px;
  padding: 16px 20px;
  margin: 24px 0;
}
ul, ol { padding-left: 1.3em; }
li { margin: 4px 0; }
footer {
  padding-top: 20px;
  padding-bottom: 32px;
  border-top: 1px solid var(--border);
  color: var(--muted);
  font-size: .9rem;
}