:root {
  --bg: #f6f8fa;
  --surface: #ffffff;
  --text: #1b2a35;
  --muted: #5b6b77;
  --brand: #0e4e72;
  --accent: #1f8a5b;
  --border: #dde4ea;
}
@media (prefers-color-scheme: dark) {
  :root {
    --bg: #0f1a22;
    --surface: #162430;
    --text: #e6edf2;
    --muted: #9fb0bc;
    --brand: #6fb3dc;
    --accent: #5cc792;
    --border: #2a3a47;
  }
}
* { box-sizing: border-box; }
body {
  margin: 0;
  background: var(--bg);
  color: var(--text);
  font: 16px/1.6 -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif;
}
header {
  background: var(--brand);
  color: #fff;
  padding: 20px 16px;
}
@media (prefers-color-scheme: dark) { header { color: #0f1a22; } }
header a { color: inherit; text-decoration: none; font-weight: 700; font-size: 20px; }
main {
  max-width: 760px;
  margin: 24px auto;
  padding: 24px 16px;
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: 12px;
}
h1 { font-size: 28px; line-height: 1.25; margin-top: 0; }
h2 { font-size: 20px; margin-top: 32px; }
a { color: var(--brand); }
.muted { color: var(--muted); font-size: 14px; }
.box {
  border-left: 4px solid var(--accent);
  padding: 12px 16px;
  background: var(--bg);
  border-radius: 8px;
}
ul, ol { padding-left: 22px; }
footer { text-align: center; padding: 16px; color: var(--muted); font-size: 14px; }
footer a { margin: 0 8px; }