vertical divider less mixin

.vertical-divider(@color: #fff){
    position: relative;

    &:before, &:after {
        content: "";
        position: absolute;
        top: 0;
        bottom: 0;
        width: 1px;
        background-color: @color;
    }

    &:before { left: 0; }
    &:after { right: -1px; }

    &:first-child:before, &:last-child:after { display: none; }
}