:root {
  color-scheme: light dark;
  --bg: #ffffff;
  --fg: #1f2328;
  --muted: #656d76;
  --border: #d0d7de;
  --surface: #f6f8fa;
  --link: #0969da;
  --focus: #1f6feb;
}

@media (prefers-color-scheme: dark) {
  :root {
    --bg: #0d1117;
    --fg: #e6edf3;
    --muted: #8b949e;
    --border: #30363d;
    --surface: #161b22;
    --link: #79c0ff;
    --focus: #2f81f7;
  }
}

* {
  box-sizing: border-box;
}

body {
  margin: 0;
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif;
  line-height: 1.7;
  color: var(--fg);
  background: var(--bg);
}

.site {
  max-width: 760px;
  margin: 40px auto;
  padding: 0 20px 48px;
}

h1 {
  margin: 0 0 0.4em;
  font-size: 1.75rem;
  line-height: 1.3;
}

h2 {
  margin-top: 1.9em;
  margin-bottom: 0.5em;
  padding-bottom: 4px;
  border-bottom: 1px solid var(--border);
  font-size: 1.2rem;
}

p {
  margin: 0 0 1em;
}

.updated {
  margin-bottom: 1.2rem;
  font-size: 0.9rem;
  color: var(--muted);
}

a {
  color: var(--link);
}

a:focus-visible {
  outline: 2px solid var(--focus);
  outline-offset: 2px;
  border-radius: 2px;
}

ul {
  padding-left: 1.4em;
}

li {
  margin-bottom: 0.35em;
}

code {
  padding: 0.15em 0.35em;
  border-radius: 4px;
  background: var(--surface);
}

.toc {
  margin: 1.2rem 0 1.8rem;
  padding: 0.9rem 1rem;
  border: 1px solid var(--border);
  border-radius: 8px;
  background: var(--surface);
}

.toc h2 {
  margin-top: 0;
  border: 0;
  padding: 0;
  font-size: 1rem;
}

.toc ul {
  margin: 0.7rem 0 0;
}

.url-list code {
  font-size: 0.95em;
}

.back-link {
  margin-top: 2rem;
  font-size: 0.95rem;
}