div#Header {
/*    background-image:url(links.png);
    background-size: cover;
    background-position:0% 80%;
    background-color:rgba(74,100,139);*/
    background-color:rgba(54,100,139);  
}
@media screen and (max-width: 50em) {
    div#KopfS  {
        background-image:url(Praxis.png);
    }
}