overflow-x issue; forced scroll

In Zita theme, I have a container set to max-width: 830px. When a long faq causes vertical overflow in browser, horizonal scrollbar also appears, the container is pushed left of header margin and the whole container can be scrolled horizontally.

The faq page is the only one that does this. I have other pages that fill the container and overflow vertically, but they don’t do this.

I’ve poked around in Notepad++ and haven’t figured out a fix yet. Ideas?