ideas for how to get rid of kubrick artifact in theme? thanks!

Hi all.

My theme is a modification of Kubrick. Can see my blog here.

https://kirstenmortensen.com/

On either side of the page there are vertical gray bars. I don’t want them there. I want the white background to be flush with the chartreuse border.

I’ve combed the code trying to figure out what is throwing up those bars and I am totally stumped.

I’ve even tried searching for every color setting in the code to find where something is set to display in gray!!!

No luck!

Anybody out there willing to offer some suggestions on what to try?

Thanks so much!