Home Page Widget CSS Misbehaving

I finally was able to get some custom widget areas onto the home page with Elements. Part of the PHP code included some markup for left and right floated sections, then a clearing division, and a full width widget under that.

You can see it on the testbed here:
https://tvhoa.mytestbed.com

However, no matter what I do, I cannot get the thing to honor my CSS. There isn't anything in the code or the CSS that should be prohibiting it. Any ideas? So close, and yet so far. :)