setting treetable node color and font size, and treetable background

i created a treetable and use setContainerDatasource() to fill the details parents node and children node. now. i want to change the treetable background color, node color and size, anyone can give me some advices?? thanks.

i tried using normal method: changing style.css file and set treetable.addstylename() to set, it is not working. so wanna someone help me .