Are you using the .css file? Fonts tags have been deprecated since html 3 and are now up to html 5 which requirs about everthing be controled by the css file from font size, color, weight, style, font family, positioning. Some of the stuff they have deprecated has quit working.
I have been updating my pages to validate under html5, a lot of stuff I was taught to do under html4 is now frowned on. Like summery tags in Tables. For the most part html5 is harder, you could align a whole page with div align=center which is now highly depreciated and requires a lot more coding, there are at least half a dozen alignment commands. text-align works on text but not any other element.
Validate the XHTML http://validator.w3.org/check/referer and CSS http://jigsaw.w3.org/css-validator/