In some cases it is as simple as putting the css in a tiddler and taging it with the stylesheet tag. I have done this with w3css others have used basecamp or something like fontawesome.
You can include css via a tiddler with a raw tag as well.
Regards
Tony
What I know so far:
In the tiddler $:/plugins/kookma/shiraz/styles/semantic/bglowtone-colors Mohammad added the ability to change the background color of tiddlersBTW, the "period" in front of class names always confuses me, sometimes I need it, and other times no - ?