body {
  font-family: system-ui, sans-serif;
  max-width: 640px;
  margin: 4rem auto;
  padding: 0 1rem;
  line-height: 1.6;
}

h1 {
  color: #1a73e8;
}

button {
  padding: 0.5rem 1rem;
  cursor: pointer;
}