:root {
  color-scheme: light dark;
  --bg: #f6f7f9;
  --card: #ffffff;
  --text: #1c1e21;
  --muted: #5f6670;
  --border: #d9dde3;
  --accent: #1a73e8;
}

@media (prefers-color-scheme: dark) {
  :root {
    --bg: #111418;
    --card: #1b1f24;
    --text: #e8eaed;
    --muted: #9aa0a6;
    --border: #2f353c;
    --accent: #8ab4f8;
  }
}

* { box-sizing: border-box; }
[hidden] { display: none !important; }

body {
  margin: 0;
  background: var(--bg);
  color: var(--text);
  font: 16px/1.5 system-ui, -apple-system, "Segoe UI", Roboto, sans-serif;
}

main {
  max-width: 560px;
  margin: 0 auto;
  padding: 48px 16px;
}

h1 { margin: 0 0 4px; font-size: 1.6rem; }
h2 { margin: 0 0 8px; font-size: 1.1rem; }
.sub, .note { color: var(--muted); font-size: 0.9rem; }

.card {
  background: var(--card);
  border: 1px solid var(--border);
  border-radius: 12px;
  padding: 20px;
  margin: 24px 0;
}

.actions { display: flex; flex-wrap: wrap; gap: 12px; }

.btn {
  display: inline-block;
  padding: 10px 16px;
  border: 1px solid var(--border);
  border-radius: 8px;
  background: var(--card);
  color: var(--text);
  font: inherit;
  text-decoration: none;
  cursor: pointer;
}
.btn:hover { border-color: var(--accent); }

code { font-size: 0.85em; }