:root {
  color-scheme: light dark;
  --fg: #1c1c1e;
  --bg: #ffffff;
  --muted: #5b5b5f;
  --border: #e2e2e5;
  --accent: #2f5d3a;
}

@media (prefers-color-scheme: dark) {
  :root {
    --fg: #f2f2f3;
    --bg: #121214;
    --muted: #a9a9ad;
    --border: #303033;
    --accent: #7fd196;
  }
}

* {
  box-sizing: border-box;
}

html {
  -webkit-text-size-adjust: 100%;
}

body {
  margin: 0;
  padding: 0 16px 64px;
  background: var(--bg);
  color: var(--fg);
  font-family: -apple-system, BlinkMacSystemFont, "Hiragino Sans", "Segoe UI", Roboto, sans-serif;
  line-height: 1.75;
  font-size: 16px;
}

.wrap {
  max-width: 640px;
  margin: 0 auto;
}

header {
  padding: 32px 0 16px;
  border-bottom: 1px solid var(--border);
  margin-bottom: 24px;
}

h1 {
  font-size: 1.5rem;
  margin: 0 0 8px;
}

.subtitle {
  color: var(--muted);
  font-size: 0.9rem;
  margin: 0;
}

h2 {
  font-size: 1.1rem;
  margin: 2em 0 0.6em;
  padding-top: 0.2em;
  border-top: 1px solid var(--border);
}

h2:first-of-type {
  border-top: none;
  padding-top: 0;
}

h3 {
  font-size: 1rem;
  margin: 1.4em 0 0.4em;
}

p, li {
  font-size: 0.98rem;
}

ul {
  padding-left: 1.3em;
}

a {
  color: var(--accent);
  word-break: break-word;
}

.lang-switch {
  font-size: 0.9rem;
  margin-top: 8px;
}

footer {
  margin-top: 3em;
  padding-top: 1em;
  border-top: 1px solid var(--border);
  color: var(--muted);
  font-size: 0.85rem;
}