:root { --bg: #ffffff; --fg: #1a1a1a; --muted: #5f6368; --link: #0b57d0; }
@media (prefers-color-scheme: dark) {
  :root { --bg: #121212; --fg: #ececec; --muted: #a0a4a8; --link: #8ab4f8; }
}
* { box-sizing: border-box; }
body { margin: 0; background: var(--bg); color: var(--fg);
  font: 17px/1.6 system-ui, -apple-system, "Segoe UI", Roboto, sans-serif; }
main { max-width: 680px; margin: 0 auto; padding: 40px 16px 64px; }
h1 { font-size: 2rem; line-height: 1.2; margin: 0 0 8px; }
h2 { font-size: 1.15rem; margin: 32px 0 8px; }
a { color: var(--link); }
.muted { color: var(--muted); margin-top: 0; }
.lead { font-size: 1.15rem; }
.back { margin: 0 0 24px; }
ul { padding-left: 1.2em; }
li { margin: 6px 0; }