Hello, @TFS,
In order to solve your issue simply go to the Dashboard >> XStore >> Theme Settings >> Theme Custom CSS >> Global and then paste the below code at the bottom of the CSS box there.
.page-id-5663 .cart-checkout-nav{margin-bottom:0px !important;}
Then save settings and check back to your site after clearing the browser cache.
The result will appear like this: Under Private Content Area:
Regards 8Themes Team.