#Logo {

position: relative; 
top: 300px;
transition: transform .25s ease;

}

#Logo:hover {

transform: scale(1.5);

}

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