:root {
  --bg: #f4f7f9;
  --card: #ffffff;
  --ink: #0f1720;
  --muted: #5b6775;
  --brand: #0d9ec7;
  --line: rgba(15, 23, 32, 0.08);
  --max: 44rem;
}
* { box-sizing: border-box; }
html { color-scheme: light dark; }
body {
  margin: 0;
  font: 16px/1.55 -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
  color: var(--ink);
  background: var(--bg);
}
@media (prefers-color-scheme: dark) {
  :root {
    --bg: #0b1116;
    --card: #141c24;
    --ink: #e8eef4;
    --muted: #9aa8b6;
    --line: rgba(255,255,255,0.08);
  }
}
header, main, footer { max-width: var(--max); margin: 0 auto; padding: 1.25rem 1.25rem; }
header { padding-top: 2rem; }
header a.brand {
  color: var(--brand);
  text-decoration: none;
  font-weight: 700;
  letter-spacing: -0.02em;
}
nav { margin-top: 0.75rem; display: flex; flex-wrap: wrap; gap: 0.75rem 1rem; }
nav a { color: var(--muted); text-decoration: none; font-size: 0.95rem; }
nav a:hover { color: var(--brand); }
.card {
  background: var(--card);
  border: 1px solid var(--line);
  border-radius: 16px;
  padding: 1.25rem 1.35rem;
  box-shadow: 0 8px 24px rgba(0,0,0,0.04);
}
h1 { font-size: 1.75rem; line-height: 1.2; margin: 0 0 0.5rem; letter-spacing: -0.03em; }
h2 { font-size: 1.15rem; margin: 1.5rem 0 0.5rem; }
p, li { color: var(--ink); }
.muted, .meta { color: var(--muted); font-size: 0.95rem; }
ul { padding-left: 1.2rem; }
a { color: var(--brand); }
footer { color: var(--muted); font-size: 0.9rem; padding-bottom: 3rem; }