:root {
  color-scheme: light dark;
  --bg: #f5f6f8;
  --card: #ffffff;
  --text: #1c1e21;
  --muted: #6b7280;
  --accent: #2563eb;
  --error: #dc2626;
}

@media (prefers-color-scheme: dark) {
  :root {
    --bg: #111318;
    --card: #1c1f26;
    --text: #e5e7eb;
    --muted: #9ca3af;
  }
}

* { box-sizing: border-box; }

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

.card {
  background: var(--card);
  border-radius: 12px;
  box-shadow: 0 4px 24px rgb(0 0 0 / 10%);
  padding: 2.5rem 3rem;
  max-width: 28rem;
  text-align: center;
}

h1 {
  margin-top: 0;
  color: var(--accent);
  font-size: 1.5rem;
  letter-spacing: 0.02em;
}

.welcome { font-size: 1.25rem; }
.muted { color: var(--muted); font-size: 0.875rem; }
.error { color: var(--error); font-weight: 600; }
code { font-size: 0.85em; }