body {
  margin: 0;
  min-height: 100vh;
  display: grid;
  place-items: center;
  font-family: system-ui, sans-serif;
  background: linear-gradient(135deg, #667eea, #764ba2);
}

.card {
  background: #fff;
  padding: 32px 40px;
  border-radius: 16px;
  box-shadow: 0 20px 60px rgba(0, 0, 0, .25);
  text-align: center;
  max-width: 440px;
}

h1 { margin-top: 0; }

a { color: #667eea; }

button {
  border: 0;
  border-radius: 8px;
  padding: 10px 20px;
  font-size: 15px;
  background: #667eea;
  color: #fff;
  cursor: pointer;
}