Creating a Custom CSS for P:M?

[Chromewhip]

Anybody know where I might look to get started on a task like this? Been looking all over, not a lot of information out there. Specifically what I'm trying to do is change the shape of the CSP Icons/Player1-4 silloutes. All I could find online is CSS organizer, which does not apply to my scenario :/ Any help would be appreciated, I'm a semi-competent modder(worked with PSA a bunch, done some brawlbox work).

 

[Y-L]

I would post this in customized content.