:root {
  color-scheme: light dark;
  --bg: #f6f7f9;
  --fg: #1a1d22;
  --muted: #5b6470;
  --card: #ffffff;
  --border: #d8dde3;
  --accent: #2b6cb0;
  --accent-hover: #234e7d;
  --error-bg: #fdecea;
  --error-fg: #8a1f1c;
}
@media (prefers-color-scheme: dark) {
  :root {
    --bg: #14171c;
    --fg: #e6e9ef;
    --muted: #98a0ad;
    --card: #1c2026;
    --border: #2a2f37;
    --accent: #4a90e2;
    --accent-hover: #6aa9f1;
    --error-bg: #3a1d1c;
    --error-fg: #ffb4b0;
  }
}
* { box-sizing: border-box; }
html, body { height: 100%; }
body {
  margin: 0;
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
  background: var(--bg);
  color: var(--fg);
  display: grid;
  place-items: center;
  padding: 1rem;
}
.card {
  background: var(--card);
  border: 1px solid var(--border);
  border-radius: 12px;
  padding: 2rem;
  width: 100%;
  max-width: 360px;
  box-shadow: 0 4px 24px rgba(0, 0, 0, 0.06);
}
h1 {
  margin: 0 0 0.25rem;
  font-size: 1.5rem;
  font-weight: 600;
}
.subtitle {
  margin: 0 0 1.25rem;
  color: var(--muted);
  font-size: 0.95rem;
}
.error {
  background: var(--error-bg);
  color: var(--error-fg);
  border-radius: 8px;
  padding: 0.65rem 0.85rem;
  margin-bottom: 1rem;
  font-size: 0.9rem;
}
form { display: grid; gap: 0.85rem; }
label { display: grid; gap: 0.3rem; font-size: 0.85rem; color: var(--muted); }
input[type="text"], input[type="password"] {
  font: inherit;
  padding: 0.6rem 0.75rem;
  background: var(--bg);
  border: 1px solid var(--border);
  border-radius: 8px;
  color: var(--fg);
  outline: none;
  transition: border-color 0.15s ease;
}
input[type="text"]:focus, input[type="password"]:focus {
  border-color: var(--accent);
}
button {
  margin-top: 0.5rem;
  font: inherit;
  font-weight: 600;
  padding: 0.7rem 1rem;
  background: var(--accent);
  color: #fff;
  border: 0;
  border-radius: 8px;
  cursor: pointer;
  transition: background-color 0.15s ease;
}
button:hover { background: var(--accent-hover); }
.footer {
  margin: 1.25rem 0 0;
  color: var(--muted);
  font-size: 0.8rem;
  text-align: center;
}
a { color: var(--accent); }