:root {
  color-scheme: light dark;
  --fg: #111;
  --muted: #6b7280;
  --accent: #2563eb;
  --bg: #fff;
  --card: #f8fafc;
  --border: #e5e7eb;
}
@media (prefers-color-scheme: dark) {
  :root {
    --fg: #f1f5f9;
    --muted: #94a3b8;
    --accent: #60a5fa;
    --bg: #0b1020;
    --card: #111827;
    --border: #1f2937;
  }
}
* { box-sizing: border-box; }
html, body { margin: 0; padding: 0; }
body {
  font-family: -apple-system, BlinkMacSystemFont, "SF Pro Text", "Segoe UI",
               Roboto, Helvetica, Arial, sans-serif;
  background: var(--bg);
  color: var(--fg);
  line-height: 1.6;
}
.container {
  max-width: 760px;
  margin: 0 auto;
  padding: 64px 24px 96px;
}
header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
  padding-bottom: 24px;
  border-bottom: 1px solid var(--border);
  margin-bottom: 32px;
}
header h1 {
  margin: 0;
  font-size: 1.25rem;
  letter-spacing: -0.01em;
}
header nav a {
  margin-left: 16px;
  color: var(--muted);
  text-decoration: none;
  font-size: 0.95rem;
}
header nav a:hover { color: var(--accent); }
h1, h2, h3 { letter-spacing: -0.02em; }
h1.title { font-size: 2.25rem; margin: 0 0 0.5rem; }
.lede { color: var(--muted); margin-bottom: 2rem; }
main h2 { margin-top: 2.5rem; }
main h3 { margin-top: 1.75rem; }
ul { padding-left: 1.25rem; }
li { margin: 0.25rem 0; }
.card {
  background: var(--card);
  border: 1px solid var(--border);
  border-radius: 12px;
  padding: 20px 24px;
  margin: 24px 0;
}
footer {
  margin-top: 64px;
  padding-top: 24px;
  border-top: 1px solid var(--border);
  color: var(--muted);
  font-size: 0.875rem;
  display: flex;
  justify-content: space-between;
  flex-wrap: wrap;
  gap: 8px;
}
a { color: var(--accent); }
a:hover { text-decoration: underline; }