.container {
    max-width: 400px;
    margin: 0 auto;
    text-align: center;
  }
  
  input[type="number"], button {
    display: block;
    margin-bottom: 10px;
  }
  
  button {
    padding: 5px 10px;
  }
  
  h2 {
    margin-top: 20px;
  }