.button {
    background-color: #4CAF50; /* Green */
    border: none;
    color: white;
    padding: 15px 32px;
    text-align: center;
    text-decoration: none;
    display: inline-block;
    font-size: 25px;
  }

  .center {
    margin-top: 20%;
    text-align: center;
  }
  .page1{
    position: fixed;
margin-top: -100px;
margin-left: -100px;
    width: 2500px;
    height:  2500px;
    background-color: green;
    -webkit-transition: background-color 1000ms linear;
    -moz-transition: background-color 1000ms linear;
    -o-transition: background-color 1000ms linear;
    -ms-transition: background-color 1000ms linear;
    transition: background-color 1000ms linear;
  }
  .alba{
    background-color: #FFBF00;
  }
  .red{
    background-color: red;
  }