CSS tweak for my site?

Hello Max. I was wondering if you would be able to help me with some CSS to make this work for my site.

A problem I have is that whenever the state of the widget goes to fixed, it doesn’t respect my header. So the widget looks like it’s covered up by my header.

I think some padding would solve it, but i’m unable to find what element I need to identify. The last thing is that when widgets are in a fixed state, they overlap each other.

Could I possibly send you credentials to tweak? And/or maybe you have a donation link?