.galerieholder {
 column-count: 3;
 column-gap: 20px;
 max-width: 1600px;
 margin: 0 auto;
}

.galerieblock {
display: inline-block;
background-color: grey;
padding: 20px;
margin: 0 0 20px;
width: 100%;
box-sizing: border-box;

}

.galerieblock img {
 width: 100%;

}

@media  (max-width: 768px)  {

  #teaser { height: 300px; }
 
 .galerieholder {
    column-count: 2;
    
   }
   
}

@media  (max-width: 575px)  {

  #teaser { height: 250px; }
 
 .galerieholder {
    column-count: 1;
    
   }
   
}