[otrs] Changing Priority color in 2.4

With OTRS 2.2 I managed to figure out how to assign colors to each priority level as well as cause the entire ticket to be highlighted as a certain color. I'm testing out 2.4 but for the life of me I can't see how to make the same change as I was able to make in 2.2. That particular file (css.dtl) no longer exists. Can anyone point me in the right direction?