Hi Gerald,
Add a class name like my-overlap class to column that you want to overlap, then add this CSS :
@media (min-width:979px){
.my-overlap{
position:relative;
top:-150px;
}
}
Negative margin is not recommended because it will still take it position even after it moves on top and will give you blank space right where it should originally.
I also notice a console error on your site because of the code you have added on Global JS.
<div id="fb-root"></div>
<script>(function(d, s, id) {
var js, fjs = d.getElementsByTagName(s)[0];
if (d.getElementById(id)) return;
js = d.createElement(s); js.id = id;
js.src = "//connect.facebook.net/de_DE/sdk.js#xfbml=1&version=v2.10&appId=111836832718705";
fjs.parentNode.insertBefore(js, fjs);
}(document, 'script', 'facebook-jssdk'));</script> </script>
Note that global JS is intended for JS script only and the following line <div id="fb-root"></div>
will cause error because that is a html code. Add something like this instead on your child theme functions.php file:
/*Pixel Code*/
function fb_print_pixel_event(){
?>
<!-- FB CODE HERE -->
<?php }
add_action( 'wp_head', 'fb_print_pixel_event' );
For more customization guide, see this: https://theme.co/apex/forum/t/customizations-actions-and-filters-in-x/208
Hope this helps.