Template Question

I'm trying to restyle and retool my blog, and in going through the stylesheet I see a definition for a CSS div id with the name #banner-commentspop. I've searched through all the other templates for my site, and can't find any reference to a <div id="banner-commentspop">.

Whenever I update a stylesheet or template, I like to prune out unused or unnecessary code. Is there some external template for the comments that incorporates this style definition, or can I safely delete it?

Thanks for any insight!