Can we tweak how things appear on mobile?

Hi - Are we able to format how the community looks on mobile? A couple places I’d change:

We’re a private community and the image behind the login page (added via CSS) is really cut off. I’d probably resize.

For the top banner - we have the design mostly on the right hand side. None of that shows on mobile; it’s just orange. 

The content is there; the formatting just doesn’t translate well.