body {
  font-family: Arial, sans-serif;
  margin: 40px;
}
input, button {
  padding: 8px;
  margin: 5px;
  width: 100%;
  max-width: 400px;
}
form {
  max-width: 400px;
  margin: auto;
}
h1 {
  text-align: center;
}