:root {
  color-scheme: light dark;
  --text: #1d1d1f;
  --secondary: #6e6e73;
  --background: #ffffff;
  --surface: #f5f5f7;
  --accent: #0066cc;
  --rule: #d2d2d7;
}

@media (prefers-color-scheme: dark) {
  :root {
    --text: #f5f5f7;
    --secondary: #a1a1a6;
    --background: #000000;
    --surface: #1d1d1f;
    --accent: #2997ff;
    --rule: #424245;
  }
}

* { box-sizing: border-box; }

body {
  margin: 0;
  background: var(--background);
  color: var(--text);
  font: 17px/1.55 -apple-system, BlinkMacSystemFont, "SF Pro Text", "Helvetica Neue", sans-serif;
  -webkit-font-smoothing: antialiased;
}

main, header, footer {
  max-width: 720px;
  margin: 0 auto;
  padding: 0 16px;
}

header {
  display: flex;
  align-items: center;
  gap: 16px;
  padding-top: 32px;
  padding-bottom: 16px;
}

header a { color: var(--text); text-decoration: none; font-weight: 600; }
header nav { margin-left: auto; display: flex; gap: 20px; }
header nav a { font-weight: 400; color: var(--secondary); }
header nav a[aria-current="page"] { color: var(--text); }

h1 { font-size: 40px; line-height: 1.1; letter-spacing: -0.02em; margin: 32px 0 8px; }
h2 { font-size: 24px; margin: 40px 0 8px; }
h3 { font-size: 19px; margin: 24px 0 4px; }
p, li { margin: 8px 0; }
a { color: var(--accent); }
.lead { font-size: 21px; color: var(--secondary); margin-top: 0; }
.updated { color: var(--secondary); font-size: 15px; }

.card {
  background: var(--surface);
  border-radius: 16px;
  padding: 16px 20px;
  margin: 16px 0;
}

footer {
  border-top: 1px solid var(--rule);
  margin-top: 64px;
  padding-top: 16px;
  padding-bottom: 48px;
  color: var(--secondary);
  font-size: 14px;
}

footer a { color: var(--secondary); }