Separating CSS Classes with prefixes. dialog-ui-xyz, progressbar-ui-xyz

Separating CSS Classes with prefixes. dialog-ui-xyz, progressbar-ui-xyz

How can i seperate the Classes for the UI elements?
I want to have compleatley different styles for each element, so my idear was that i add prefixes to the class names of the elements. How can i do this?

The UI dont even share the classes.