body {
  font: 1rem system-ui, sans-serif;
  line-height: 1.6;
  margin: 3rem 1rem;
}

main {
  max-width: 640px;
  margin: auto;
}

input {
  width: 5rem;
  padding: .5rem;
}

button {
  padding: .5rem 1rem;
  cursor: pointer;
}

button:disabled {
  cursor: not-allowed;
}

input:focus-visible,
button:focus-visible {
  outline: 2px solid currentColor;
  outline-offset: 3px;
}