:root {
  --bg: #ffffff;
  --ink: #1d2328;
  --muted: #5c6670;
  --line: #e2e5e8;
  --link: #0f5c63;
}
@media (prefers-color-scheme: dark) {
  :root { --bg: #14181c; --ink: #e6e9ec; --muted: #9aa4ae; --line: #2a3138; --link: #7cc7cf; }
}
* { box-sizing: border-box; }
body { margin: 0; background: var(--bg); color: var(--ink); font: 15px/1.6 -apple-system, BlinkMacSystemFont, "Segoe UI", Inter, Roboto, sans-serif; }
header { position: sticky; top: 0; display: flex; flex-wrap: wrap; align-items: center; gap: 8px 20px; padding: 12px max(16px, calc((100% - 760px) / 2)); background: var(--bg); border-bottom: 1px solid var(--line); }
nav { display: flex; flex-wrap: wrap; gap: 4px 14px; font-size: 13px; }
nav a { color: var(--muted); text-decoration: none; }
nav a:hover { color: var(--ink); }
main { max-width: 760px; margin: 0 auto; padding: 24px 16px 64px; }
h1 { font-size: 24px; line-height: 1.25; margin: 8px 0 4px; }
h2 { font-size: 18px; margin: 36px 0 8px; padding-top: 8px; border-top: 1px solid var(--line); }
h3 { font-size: 15px; margin: 18px 0 4px; }
section { scroll-margin-top: 64px; }
.meta { color: var(--muted); font-size: 13px; margin-top: 0; }
a { color: var(--link); }
ul { padding-left: 20px; }
li { margin: 4px 0; }
@media (prefers-color-scheme: dark) { header img { filter: invert(1) hue-rotate(180deg); } }