:root {
  color-scheme: dark;
  --bg: #121212;
  --card: #1e1e1e;
  --border: #2b2b43;
  --text: #e6e6e6;
  --muted: #a0a4ad;
  --accent: #26a69a;
  --error: #ff8a80;
}
* {
  box-sizing: border-box;
}
body {
  margin: 0;
  min-height: 100vh;
  display: grid;
  place-items: center;
  padding: 16px;
  background: var(--bg);
  color: var(--text);
  font: 15px/1.5 system-ui, -apple-system, 'Segoe UI', sans-serif;
}
.card {
  width: 100%;
  max-width: 420px;
  padding: 28px 24px;
  background: var(--card);
  border: 1px solid var(--border);
  border-radius: 10px;
}
h1 {
  margin: 0 0 8px;
  font-size: 20px;
}
p {
  margin: 0 0 18px;
  color: var(--muted);
}
button {
  display: block;
  width: 100%;
  padding: 10px 14px;
  margin-bottom: 10px;
  border: 0;
  border-radius: 6px;
  background: var(--accent);
  color: #fff;
  font: inherit;
  font-weight: 600;
  cursor: pointer;
}
button.secondary {
  background: transparent;
  border: 1px solid var(--border);
  color: var(--text);
}
button:disabled {
  opacity: 0.6;
  cursor: default;
}
#msg {
  min-height: 1.5em;
  margin: 8px 0 0;
}
#msg.error {
  color: var(--error);
}
[hidden] {
  display: none !important;
}