:root {
  --bg: #ffffff;
  --text: #1d1d1f;
  --muted: #6e6e73;
  --line: #d2d2d7;
  --link: #0a66c2;
  color-scheme: light dark;
}

@media (prefers-color-scheme: dark) {
  :root {
    --bg: #1c1c1e;
    --text: #f5f5f7;
    --muted: #a1a1a6;
    --line: #3a3a3c;
    --link: #64a8f0;
  }
}

* { box-sizing: border-box; }

body {
  margin: 0;
  background: var(--bg);
  color: var(--text);
  font: 17px/1.55 -apple-system, BlinkMacSystemFont, "Helvetica Neue", Arial, sans-serif;
}

main {
  max-width: 680px;
  margin: 0 auto;
  padding: 64px 20px 48px;
}

h1 { font-size: 40px; line-height: 1.15; margin: 0 0 8px; letter-spacing: -0.02em; }
h2 { font-size: 21px; margin: 40px 0 8px; }
p, ul { margin: 0 0 12px; }
ul { padding-left: 22px; }
li { margin-bottom: 6px; }
.lede { color: var(--muted); font-size: 19px; margin: 0; }
.back { margin: 0 0 16px; font-size: 15px; }
a { color: var(--link); text-decoration: none; }
a:hover { text-decoration: underline; }
code { font: 15px ui-monospace, SFMono-Regular, Menlo, monospace; }

footer {
  margin-top: 48px;
  padding-top: 16px;
  border-top: 1px solid var(--line);
  font-size: 15px;
}

@media (max-width: 480px) {
  main { padding-top: 40px; }
  h1 { font-size: 32px; }
}