Would you consider a link to your site? I'm terrible with CSS but you can experiment with it with Chrome's (or other browsers') developer tools
Well, right now the site is blocked from the public Internet... there's no way to access it unless your IP is exempted in the server's filter rules. Only a few of the admins currently have access to it. I'm terrible with CSS too, obviously. But I'm fairly sure the directives in additional.css are correct. I suspect the problem is with the </div> tag placement in post_thanks_postbit_info, but there may also be something which should be included in the code that's not. I'm just hoping someone can tell me what that 'something' might be and/or where I've gone wrong on the tag placement.