:root {
  --bg: #ffffff;
  --fg: #1c1c1e;
  --muted: #6e6e73;
  --accent: #0a84ff;
  --rule: #e5e5ea;
}

@media (prefers-color-scheme: dark) {
  :root {
    --bg: #000000;
    --fg: #f2f2f7;
    --muted: #8e8e93;
    --accent: #0a84ff;
    --rule: #2c2c2e;
  }
}

* { box-sizing: border-box; }

body {
  margin: 0;
  padding: 0 1.25rem;
  background: var(--bg);
  color: var(--fg);
  font: 17px/1.6 -apple-system, BlinkMacSystemFont, "SF Pro Text", "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
  -webkit-font-smoothing: antialiased;
}

main {
  max-width: 44rem;
  margin: 0 auto;
  padding: 3rem 0 4rem;
}

header nav {
  display: flex;
  gap: 1.25rem;
  padding-bottom: 1.5rem;
  border-bottom: 1px solid var(--rule);
  margin-bottom: 2rem;
  font-size: 0.95rem;
}

h1 { font-size: 2rem; line-height: 1.2; margin: 0 0 0.5rem; letter-spacing: -0.02em; }
h2 { font-size: 1.25rem; margin: 2.25rem 0 0.5rem; }
p, li { margin: 0.5rem 0; }
ul { padding-left: 1.25rem; }

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

.meta { color: var(--muted); font-size: 0.95rem; margin-bottom: 2rem; }
.summary {
  padding: 1rem 1.25rem;
  border: 1px solid var(--rule);
  border-radius: 12px;
  margin: 1.5rem 0;
}

footer {
  margin-top: 4rem;
  padding-top: 1.5rem;
  border-top: 1px solid var(--rule);
  color: var(--muted);
  font-size: 0.9rem;
}