*, *::before, *::after {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

:root {
  --bg: #0d1117;
  --surface: #161b22;
  --border: #30363d;
  --text: #e6edf3;
  --muted: #8b949e;
}

html, body {
  height: 100%;
}

body {
  background-color: var(--bg);
  color: var(--text);
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", system-ui, sans-serif;
  display: flex;
  align-items: center;
  justify-content: center;
}

main {
  width: 100%;
  padding: 2rem;
  display: flex;
  justify-content: center;
}

.card {
  max-width: 420px;
  width: 100%;
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: 8px;
  padding: 2.5rem 2rem;
  text-align: center;
  animation: fadein 0.6s ease;
}

h1 {
  font-size: 1.75rem;
  font-weight: 600;
  letter-spacing: 0.02em;
  color: var(--text);
}

hr {
  border: none;
  border-top: 1px solid var(--border);
  margin: 1.25rem 0;
}

p {
  font-size: 0.95rem;
  color: var(--muted);
  letter-spacing: 0.03em;
}

@keyframes fadein {
  from { opacity: 0; transform: translateY(8px); }
  to   { opacity: 1; transform: translateY(0); }
}