Issues With HTML Rendering Correctly

Has anyone else here had issues with building their own HTML/CSS code elsewhere and trying to paste into your Zoho site? I've tried several different times with several different embed codes and still the same result. Using a test page, you can see an example here: http://www.realtimehockey.net/testing.html As you can see the tabbed content isn't rendering correctly. I have tested this in no less than 5 different editors and it's worked fine. At one point support used to respond in a timely manner but, that has since ceased. At one point, Support did tell that their CSS can "override" any CSS you might have written so, I don't know if that's the issue or not. If anyone has experienced this issue, please let me know if you found a fix. Thanks in advance for any assistance you may be able to offer.