:root {
  --bg: #f6f6f4;
  --panel: #ffffff;
  --fg: #1d1f24;
  --muted: #5f636b;
  --line: #d9d9d4;
  --accent: #2f4fd1;
  --on-accent: #ffffff;
  --error: #b42318;
  color-scheme: light dark;
}

@media (prefers-color-scheme: dark) {
  :root {
    --bg: #16171a;
    --panel: #1f2125;
    --fg: #ececea;
    --muted: #a0a3ab;
    --line: #363940;
    --accent: #8ea2ff;
    --on-accent: #10131c;
    --error: #ff8a7a;
  }
}

* { box-sizing: border-box; }

body {
  margin: 0;
  min-height: 100vh;
  display: grid;
  place-items: center;
  padding: 16px;
  background: var(--bg);
  color: var(--fg);
  font: 16px/1.5 system-ui, -apple-system, "Segoe UI", sans-serif;
}

.card {
  width: 100%;
  max-width: 360px;
  padding: 28px 24px;
  background: var(--panel);
  border: 1px solid var(--line);
  border-radius: 12px;
}

h1 { margin: 0 0 20px; font-size: 1.35rem; font-weight: 600; }

form { display: flex; flex-direction: column; gap: 10px; }

label { font-size: .9rem; color: var(--muted); }

input[type="password"] {
  font: inherit;
  font-size: 1.5rem;
  letter-spacing: .4em;
  text-align: center;
  padding: 10px 12px;
  border: 1px solid var(--line);
  border-radius: 8px;
  background: var(--bg);
  color: var(--fg);
}

input:focus-visible, button:focus-visible, a:focus-visible {
  outline: 2px solid var(--accent);
  outline-offset: 2px;
}

button {
  font: inherit;
  font-weight: 600;
  padding: 10px 14px;
  border: 0;
  border-radius: 8px;
  background: var(--accent);
  color: var(--on-accent);
  cursor: pointer;
}

.error { margin: 0; min-height: 1.5em; color: var(--error); font-size: .9rem; }

a { color: var(--accent); }