ITSSTOOLS/datamodels/2.x/sample-portal-alter-twig/custom.css

.sidebar{
    display: none;
}
@media (min-width: 768px){
    .sidebar{
        display: block;
        position: fixed;
        top: 0px;
        bottom: 0px;
        left: 0px;
        padding-top: 80px;
    }
}