PopUp Pro - custom classes

I know it there is a numeric class. I was hoping to be able to add a class that is a little more decipherable and easier to use. For example, some pop-ups are exit-intent based. I want those to be styled differently from the click-spawned pop-ups. It's a little unwieldy to account for all the different the wdpu-xxxx classes in CSS. Was hoping to use a categorical class for each pop-up type and assign it to the pop-ups.