What I stated is any main stream forum has a set guideline of styles they must follow as far as class colors. We load the forums stylesheet so I do not follow you at all here. Every company that makes themes for the top forums must follow the set call names.
tcat is tcat in every vbulletin stylesheet. You can change the color anytime you want.
In ib2 if you change the color definitions you export this css file to disk and photopost loads it.
Since we load the stylesheets from the forum I do not follow.