:root { color-scheme: light dark; }
body {
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif;
  max-width: 680px; margin: 0 auto; padding: 48px 20px; line-height: 1.6;
}
h1 { font-size: 2rem; margin-bottom: 0.3em; }
h2 { font-size: 1.15rem; margin-top: 1.8em; }
.muted { opacity: 0.65; }
a { color: inherit; }
footer { margin-top: 64px; font-size: 0.9rem; opacity: 0.7; display: flex; gap: 8px; }