lost the white background on interior pages

I updated today to the latest version, 2.8.4. Unfortunately I was foolish enough not to keep a record of the editing changes I had made to the template in the previous version. I had changed the colors of links and some things in the stylesheet and suppressed some stuff in the sidebar; I am using the Kubrick template.

Anyway, I got most of it back to where it had been, except for a few more glitches. The pages with the actual posts on them look fine. But now when you search for something in the archives, the white page background doesn’t extend down very far and you are reading the text against the background color instead of over white. What happened? What do I fix to get it back? You can see what I mean at