:root {
  --bg: #fafaf9;
  --fg: #1c1917;
  --muted: #78716c;
  --line: #e7e5e4;
  --accent: #2563eb;
  --warn-bg: #fef2f2;
  --warn-fg: #991b1b;
  color-scheme: light dark;
}
@media (prefers-color-scheme: dark) {
  :root {
    --bg: #1c1917;
    --fg: #f5f5f4;
    --muted: #a8a29e;
    --line: #44403c;
    --accent: #60a5fa;
    --warn-bg: #450a0a;
    --warn-fg: #fecaca;
  }
}
* { box-sizing: border-box; }
body { margin: 0; background: var(--bg); color: var(--fg); font: 15px/1.5 system-ui, sans-serif; }
header {
  display: flex; align-items: center; gap: 16px; flex-wrap: wrap;
  padding: 12px 16px; border-bottom: 1px solid var(--line);
}
h1 { font-size: 18px; margin: 0; }
nav { display: flex; gap: 4px; flex: 1; flex-wrap: wrap; }
nav button { border: 0; background: none; color: var(--muted); padding: 6px 10px; border-radius: 6px; cursor: pointer; font: inherit; }
nav button[aria-selected="true"] { color: var(--fg); background: var(--line); }
a.external { color: var(--muted); font-size: 13px; text-decoration: none; padding: 6px 10px; border-radius: 6px; }
a.external:hover { color: var(--accent); background: var(--line); }
#session { color: var(--muted); font-size: 13px; display: flex; gap: 8px; align-items: center; }
button { font: inherit; cursor: pointer; }
#session button, .login button {
  border: 1px solid var(--line); background: none; color: var(--fg); padding: 4px 10px; border-radius: 6px;
}
main { padding: 16px; max-width: 960px; margin: 0 auto; }
.caption { color: var(--muted); }
.login { display: grid; place-items: center; gap: 12px; padding: 64px 0; }
.login button { padding: 8px 16px; font-size: 15px; }
.note.warning { background: var(--warn-bg); color: var(--warn-fg); padding: 12px 16px; border-radius: 8px; }