.spaltenparent .spalte{
    width: 48%;
    float: left;
}

.spaltenparent .spalte.clear {
    clear: left;
    margin-right: 4%;
}

.spaltenparent:after{
    display: block;
    content: "";
    clear: both;
}

@media screen and (max-width: 400px) {
    .spaltenparent .spalte,
    .spaltenparent .spalte.clear{
    width: 100%;
    float: none;
}

}