Where do I set the colors for the megamenu active and hover states?

I am trying to change the button colors for the dropdown menus, the active button color and the color of the background for the hover state for the megamenu but I cannot find where those colors are set. I also cannot figure out how to find the correct class for setting the colors for just one item since I do not fully understand how the classes work in the T3 framework. I see lines like

But I am not sure if this is one single class or a combination of a few different classes grouped together. And if they are multiple classes do I look for the CSS designator for just that combination of classes or if I am trying to create a CSS rule that only affects that item do I write the designator for just that combination of classes and if that is the case how so I write that CSS rule? I need a lot of help here obviously. Anything anyone can suggest on finding out how to accomplish this I would appreciate a heads up.