Xenforo 2.X Sticky Sidebar Css

@m-sticky-top: 48px;

@media (min-width: (@xf-responsiveWide + 1px)) {

    .p-body-main--withSidebar {

        .p-body-sideNav,

        .p-body-sidebar {

            flex: 0 0 auto;

            display: block;

        }

        @supports ((position: sticky) or (position: -webkit-sticky)) {

            .p-body-sidebar {

                position: -webkit-sticky;

                position: sticky;

                top: 10px;

                & when (@xf-publicNavSticky =primary) or (@xf-publicNavSticky =all) {

                    top: @m-sticky-top * 1px + 10px;

                }

            }

        }

    }

}