Thank you, David.
Sorry for the late reply.
So. I managed to get a sticky header by the standard customization option. I also managed to get a sticky footer by adding an after_footer-hook with an element in it – https://generatepress.com/forums/topic/how-do-i-create-a-sticky-footer-bar/
Now, in order to achieve what I am going for I need to add a 4px border in both sides of the page. Top and bottom is taken care of. So how do we do this ? Is page background-color and body padding the way to go ? Or what would you do ?
Thank you.