chessmec: i meaned, that in some fields there is fixed <font color=red>blahblub</font>

Obviously, for such a thing to happen, all pages need to be revisited. You'll be needed SPAN and DIV elements, and add CLASS and ID attributed to new and existing elements. It wouldn't be much of a problem to remove the FONT elements while you're doing that. Of course, for the one person out there who managed to survive with a browser from the last century, you can keep the FONT element:

<FONT color='red'><SPAN class='unread-messages'>1234</SPAN></
FONT>