app-catalog-ui/app_catalog/static/dashboard/project/app_catalog/app_catalog.scss

.app_catalog_grid_item_hidden {
    height: 172px;
    width: 182px;
    margin: -170px 0px 0px -10px;
    opacity: 1;
    overflow: hidden;
    display: block;
    position: relative;
    background: rgba(0, 0, 0, .25);
    z-index: 100;
}