:root {
  color-scheme: light dark;
  --text: #1d1d1f;
  --muted: #6e6e73;
  --line: #d2d2d7;
  --bg: #fff;
  --accent: #0a66d8;
}
@media (prefers-color-scheme: dark) {
  :root { --text: #f5f5f7; --muted: #a1a1a6; --line: #3a3a3c; --bg: #111; --accent: #4c9bff; }
}
* { box-sizing: border-box; }
body {
  margin: 0;
  background: var(--bg);
  color: var(--text);
  font: 17px/1.55 -apple-system, BlinkMacSystemFont, "SF Pro Text", "Helvetica Neue", sans-serif;
}
main, header, footer { max-width: 40rem; margin: 0 auto; padding: 0 1.25rem; }
header { display: flex; justify-content: space-between; align-items: baseline; padding-top: 2rem; }
header a { color: var(--text); text-decoration: none; font-weight: 600; }
nav a { color: var(--muted); font-weight: 400; margin-left: 1.25rem; }
h1 { font-size: 2.4rem; line-height: 1.15; letter-spacing: -0.02em; margin: 4rem 0 1rem; }
h2 { font-size: 1.2rem; margin: 2.5rem 0 0.5rem; }
p, li { color: var(--text); }
.lede { font-size: 1.25rem; color: var(--muted); }
.muted { color: var(--muted); }
a { color: var(--accent); }
ul { padding-left: 1.2rem; }
footer { color: var(--muted); font-size: 0.9rem; border-top: 1px solid var(--line); margin-top: 4rem; padding-top: 1.25rem; padding-bottom: 3rem; }
footer a { color: var(--muted); }