how to spilt product image gallery into two columns?

Site URL: https://www.lavito.co/store-1/p/pure-side-plate

how to spilt product image gallery into two columns?

Add to Design > Custom CSS

@media screen and (min-width:768px) {
.tweak-product-basic-item-gallery-design-stacked .ProductItem-gallery-slides-item {
    width: 50%;
    float: left;
}
.tweak-product-basic-item-gallery-design-stacked .ProductItem-gallery-slides-item:nth-child(2n+1) {
    clear: left;
}
}