:root {
  color-scheme: light dark;
  --text: #1d1d1f;
  --secondary: #6e6e73;
  --background: #ffffff;
  --link: #0066cc;
  --rule: #d2d2d7;
}

@media (prefers-color-scheme: dark) {
  :root {
    --text: #f5f5f7;
    --secondary: #a1a1a6;
    --background: #000000;
    --link: #2997ff;
    --rule: #424245;
  }
}

body {
  margin: 0;
  background: var(--background);
  color: var(--text);
  font: 17px/1.6 -apple-system, BlinkMacSystemFont, "Segoe UI", Helvetica, Arial, sans-serif;
  -webkit-text-size-adjust: 100%;
}

main {
  max-width: 720px;
  margin: 0 auto;
  padding: 48px 16px 64px;
}

h1 { font-size: 2em; line-height: 1.2; margin: 0 0 0.5em; }
h2 { font-size: 1.3em; margin: 2em 0 0.5em; padding-top: 1em; border-top: 1px solid var(--rule); }

a { color: var(--link); text-decoration: none; }
a:hover { text-decoration: underline; }

ul { padding-left: 1.3em; }
li { margin: 0.3em 0; }

.subtitle { color: var(--secondary); margin-top: 0; }