body {
  font-family: sans-serif;
  background: #f0f0f0;
  padding: 2rem;
}
.container {
  max-width: 600px;
  margin: auto;
  background: white;
  padding: 2rem;
  text-align: center;
  border-radius: 12px;
  box-shadow: 0 5px 20px rgba(0,0,0,0.1);
}
button {
  margin-top: 1rem;
  padding: 0.75rem 1.5rem;
  background: #317EFB;
  color: white;
  border: none;
  border-radius: 6px;
  cursor: pointer;
}
button[disabled] {
  background: gray;
}