:root {
  color-scheme: light dark;
  --bg: #ffffff;
  --fg: #222222;
  --muted: #666666;
  --accent: #005bbb;
  --box: #f7f7f7;
}

@media (prefers-color-scheme: dark) {
  :root {
    --bg: #121212;
    --fg: #e6e6e6;
    --muted: #a0a0a0;
    --accent: #66a3ff;
    --box: #1d1d1d;
  }
}

html, body {
  margin: 0;
  padding: 0;
  background: var(--bg);
  color: var(--fg);
  font-family: system-ui, -apple-system, Segoe UI, Roboto, Ubuntu, Cantarell, "Helvetica Neue", Arial, sans-serif;
}

.page-header, .page-footer {
  padding: 1rem;
  background: var(--box);
  border-bottom: 1px solid #ddd;
}

.page-footer {
  border-top: 1px solid #ddd;
  border-bottom: none;
  text-align: center;
}

.subtitle {
  color: var(--muted);
  margin-top: 0.25rem;
}

main {
  padding: 1rem;
  max-width: 64rem;
  margin: 0 auto;
}

.iframe-container {
  margin: 1rem 0;
}

.tips ul {
  line-height: 1.6;
  padding-left: 1.25rem;
}

.tips a {
  color: var(--accent);
  text-decoration: underline;
}

.status-box {
  padding: 0.75rem 1rem;
  border: 1px solid #ddd;
  border-radius: 6px;
  background: var(--box);
}