#link11 {
     background-image: url(../bilder/einzelseiten.png);
}

#link11:hover {
     background-image: url(../bilder/einzelseiten-hover.png);
}

#link12 {
     background-image: url(../bilder/serien.png);
}

#link12:hover {
     background-image: url(../bilder/serien-hover.png);
}
#link21 {
     background-image: url(../bilder/stories.png);
}

#link21:hover {
     background-image: url(../bilder/stories-hover.png);
}