body {
  margin: 0;
  min-height: 100vh;
  display: flex;
  align-items: center;
  justify-content: center;
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
  background: whitesmoke;
  color: dimgray;
}

@media (prefers-color-scheme: dark) {
  body {
    background: midnightblue;
    color: aliceblue;
  }
}

.card {
  text-align: center;
  padding: 2.5rem 2rem;
  border-radius: 12px;
  background: white;
  box-shadow: 0 18px 40px slategray;
  width: min(90vw, 420px);
}

@media (prefers-color-scheme: dark) {
  .card {
    background: darkslategray;
    box-shadow: 0 22px 48px black;
  }
}

h1 {
  margin: 0 0 0.5rem;
  font-size: clamp(2.25rem, 4vw, 2.75rem);
}

p {
  margin: 0 0 0.75rem;
  font-size: 1.05rem;
}

.hint {
  margin-top: 1.5rem;
  font-size: 0.95rem;
  color: lightslategray;
}

@media (prefers-color-scheme: dark) {
  .hint {
    color: lightsteelblue;
  }
}