:root { color-scheme: light dark; }
* { box-sizing: border-box; }
body {
  margin: 0;
  font-family: system-ui, -apple-system, "Segoe UI", Roboto, sans-serif;
  line-height: 1.6;
  color: #1f2933;
  background: #f7f8fa;
}
.wrap { max-width: 42rem; margin: 0 auto; padding: 1rem 1.25rem; }
header.wrap { padding-top: 2.5rem; }
h1 { margin: 0; font-size: 2rem; }
h1 a { color: inherit; text-decoration: none; }
h2 { margin-top: 2rem; font-size: 1.3rem; }
h3 { margin-top: 1.5rem; font-size: 1.05rem; }
.lead { font-size: 1.15rem; }
.muted { color: #6b7280; font-size: .9rem; }
a { color: #1d4ed8; }
footer.wrap { margin-top: 3rem; border-top: 1px solid #d9dee5; color: #6b7280; font-size: .9rem; }
@media (prefers-color-scheme: dark) {
  body { color: #e5e7eb; background: #14171c; }
  a { color: #93b4ff; }
  footer.wrap { border-color: #2a2f37; }
  .muted, footer.wrap { color: #9aa3af; }
}