Trying to nest categories and subcategories on one page, as opposed to opening new pages, 7.1

Site URL: http://www.1924.us

Hey all. Trying to find a fix here, Basically what happens is we have CATEGORY >> SUBCAT. >> SUBCAT2.
Every time you click on one, it opens a new page (in the same window) with the subcategories being displayed underneath the breadcrumbs. Ideally, if I click on one category, it will bring up the sub categories, and from there, I can click on a subcategory to get to the second level of subcats, but all on one page, as opposed to opening new ones each time. Is there a way to have the products simply display without significant reload time or a new page opening?

Thanks .

Add to Design > Custom CSS

.tweak-product-list-filter-display-hide .ProductList-filter {
    display: block;
}