:root {
  --bg: #f7f8fa;
  --fg: #1f2328;
  --muted: #656d76;
  --line: #d8dee4;
  --accent: #0969da;
}
* { box-sizing: border-box; }
body {
  margin: 0;
  padding: 0 1.25rem 3rem;
  background: var(--bg);
  color: var(--fg);
  font: 16px/1.6 -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
}
header {
  max-width: 46rem;
  margin: 0 auto;
  padding: 3rem 0 1.5rem;
  border-bottom: 1px solid var(--line);
}
h1 { margin: 0; font-size: 1.75rem; letter-spacing: -0.01em; }
.sub { margin: 0.35rem 0 0; color: var(--muted); }
main { max-width: 46rem; margin: 0 auto; }
section { padding: 1.75rem 0; border-bottom: 1px solid var(--line); }
section:last-child { border-bottom: 0; }
h2 { font-size: 1.05rem; margin: 0 0 0.6rem; }
p { margin: 0 0 0.75rem; }
ul { margin: 0; padding-left: 1.2rem; color: var(--muted); }
li { margin-bottom: 0.3rem; }
pre {
  margin: 0;
  padding: 0.9rem 1rem;
  background: #fff;
  border: 1px solid var(--line);
  border-radius: 6px;
  overflow-x: auto;
}
code { font-family: ui-monospace, SFMono-Regular, Menlo, Consolas, monospace; font-size: 0.875rem; }
img { max-width: 100%; height: auto; border: 1px solid var(--line); border-radius: 6px; background: #fff; }
a { color: var(--accent); }
footer {
  max-width: 46rem;
  margin: 2.5rem auto 0;
  padding-top: 1.25rem;
  border-top: 1px solid var(--line);
  color: var(--muted);
  font-size: 0.85rem;
}
footer p { margin: 0; }