.gallery.full-gallery.de-gallery.pf_full_width.portfolio_category {
    position: relative;
    clear: both;
    z-index: 1;           /* sits under the footer */
}


.gallery.full-gallery.de-gallery.pf_full_width.portfolio_category::after {
    content: "";
    display: block;
    clear: both;
}


footer,
footer .main-footer,
footer .subfooter {
    position: relative;
    clear: both;
    z-index: 10;
}