html { 
  background: url(materiał.jpg) no-repeat center center fixed; 
 -webkit-background-size: cover;
  -moz-background-size: cover;
  -o-background-size: cover;
  background-size: cover
}




.kropkaa{color: white;
font-size: 120px;
margin-top:23%;
margin-left:50% }