:root {
  --bg: #f7f7f7;
  --fg: #1a1a1a;
  --muted: #666;
  --card: #fff;
  --border: #ddd;
  --primary: #1a73e8;
  --primary-fg: #fff;
}
@media (prefers-color-scheme: dark) {
  :root {
    --bg: #121212;
    --fg: #eee;
    --muted: #aaa;
    --card: #2c2c2c;
    --border: #444;
  }
}

* { box-sizing: border-box; }
body {
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", system-ui, sans-serif;
  margin: 0;
  padding: 2rem 1.5rem;
  max-width: 28rem;
  margin-left: auto;
  margin-right: auto;
  color: var(--fg);
  background: var(--bg);
  line-height: 1.5;
}
h1 { font-size: 1.6rem; margin: 0 0 0.5rem; }
.meta { color: var(--muted); margin-bottom: 2rem; }
.btn {
  display: block;
  padding: 0.85rem 1rem;
  margin: 0.5rem 0;
  border-radius: 0.5rem;
  background: var(--card);
  text-decoration: none;
  color: var(--fg);
  border: 1px solid var(--border);
  text-align: center;
  font-weight: 500;
}
.btn.primary {
  background: var(--primary);
  color: var(--primary-fg);
  border-color: var(--primary);
}
details { margin-top: 1.5rem; color: var(--muted); }
details summary { cursor: pointer; padding: 0.5rem 0; }
details a { color: var(--primary); }
code { font-family: ui-monospace, "SF Mono", Monaco, monospace; }