i managed to do it, heres the css:
.header-nav .header-nav-item--folder .header-nav-folder-content {
left: 0;
opacity: 1;
-webkit-transform: translate3d(0,0,0);
-moz-transform: translate3d(0,0,0);
-ms-transform: translate3d(0,0,0);
-o-transform: translate3d(0,0,0);
transform: translate3d(0,0,0);
}
but now I have a problem that if I want to click any of the sub folder items i first have to go with my cursor over the folder name to make other items clickable? Do you know a solution for that? Thanks