/*2 bilder - spaltewidth: 46%;*/
.col-md-6.portfolio-item {margin: 10px 20px 30px;}
/*3 bilder - spaltewidth: 29%;*/
.col-md-4.portfolio-item {margin: 10px 20px 30px;}
/*4 bilder - spaltewidth: 21%;*/
.col-md-3.portfolio-item {margin: 10px 20px 25px;}

.portfolio-item {
border: 0px solid #337ab7;
padding: 10px 10px 10px 10px;
box-shadow: 5px 10px 15px 1px #b7b7b7;

}

.portfolio-item {
background: #fff;
}
@media (min-width:1200px) {
    .col-md-6.portfolio-item {margin-right:14px;margin-left:15px;}
    .col-md-6 {
        width: 47.43%
    }
    .col-md-4.portfolio-item {margin-right:14px;margin-left:15px;}
    .col-md-4 {
        width: 30.77%
    }
    .col-md-3.portfolio-item {margin-right:14px;margin-left:15px;}
    .col-md-3 {
        width: 22.4%
    }

}
@media (min-width:992px) {
        .col-md-3, .col-md-4, .col-md-6{
            float: left; }

        .col-md-6.portfolio-item {margin-right:14px;margin-left:15px;}
        .col-md-6 {
            width: 46.9%
        }
        .col-md-4.portfolio-item {margin-right:14px;margin-left:15px;}
        .col-md-4 {
            width: 30.24%
        }
        .col-md-3.portfolio-item {margin-right:14px;margin-left:13px;}
        .col-md-3 {
            width: 22.3%
        }

}