:root {
  --bg: #ffffff;
  --text: #1f2937;
  --muted: #6b7280;
  --primary: #2563eb;
  --border: #e5e7eb;
}
@media (prefers-color-scheme: dark) {
  :root {
    --bg: #111827;
    --text: #e5e7eb;
    --muted: #9ca3af;
    --primary: #60a5fa;
    --border: #374151;
  }
}
* { box-sizing: border-box; }
body {
  margin: 0;
  background: var(--bg);
  color: var(--text);
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
  line-height: 1.6;
}
main { max-width: 720px; margin: 0 auto; padding: 24px 16px 64px; }
header.top { display: flex; justify-content: space-between; align-items: center; gap: 12px; margin-bottom: 8px; }
.brand { font-weight: 800; font-size: 20px; color: var(--text); text-decoration: none; }
.lang-switch button {
  background: none; border: 1px solid var(--border); color: var(--text);
  border-radius: 8px; padding: 4px 10px; font-size: 14px; cursor: pointer;
}
.lang-switch button[aria-pressed="true"] { background: var(--primary); color: #fff; border-color: var(--primary); }
h1 { font-size: 28px; margin: 24px 0 4px; }
h2 { font-size: 18px; margin: 28px 0 6px; }
p, li { font-size: 16px; }
.meta { color: var(--muted); font-size: 14px; margin-top: 0; }
a { color: var(--primary); }
ul { padding-left: 20px; }
.lang { display: none; }
.lang.active { display: block; }
footer { margin-top: 48px; padding-top: 16px; border-top: 1px solid var(--border); color: var(--muted); font-size: 14px; }
footer a { margin-right: 12px; }