html, body {
  background-color: white;
  background-image: url("../Practica1/background.jpg");
  background-attachment: fixed;
  background-repeat: repeat;
  color: black;
  font-family: Verdana;
  text-align: center;
}

div, header {
    background-color: #4CAF50;
    width: 40%;
    padding: 25px;
    border: 25px groove darkcyan;
    margin: auto;
    margin-bottom: 15px;
}