Chad –
What I mentioned here fixed this problem.
Thanks!
I had this same problem. It was a result of me using the plugin with the default “Stylesheet” option (which was for the “Twenty Twelve” theme) while I was using the “Twenty Thirteen” theme for my site. Switching to the correct “Twenty Thirteen” stylesheet fixed the problem.
Thanks for the response Chris. I appreciate the issue of dealing with with per-theme css, and I’ll take your suggestion about custom css.
Still, you may want to know that the error I observed was on the “Twenty Thirteen” theme (which was the default theme when I installed), so I anticipate this will be a problem for many of your users.