Responsive vertical header issue

[somethingworks]

Hi guys,

I've created a vertical header for this site I'm building, using custom CSS to bring in the width. But my problem is, is that on smaller screens (I'm on 27 iMac) the content bunches up underneath the header. I need it to stop at the header, if that makes sense? Please see screenshot.

 

[somethingworks]

Can anybody help with this? I know it should be a default Elementor thing, the vertical header. But it's not. So I'm assuming someone else has done this before?