form {
  width: 100%;
  max-width: 30em;
  margin: 0 auto;
  color: white;
}
form .field {
  display: flex;
  flex-flow: column;
  margin-bottom: 1em;
}
form .field input[type=text], form .field input[type=password] {
  padding: 0.5em;
}
form .field + button {
  margin-top: 1em;
}