Read / map system name - Dev / QA / PRD into portal theme

Dear gurus, is there some means by which I could map the system name (Dev / Quality / PRD) into the portal theme or some location on the portal interface, so that users can know directly without looking at the URL, which system they are in. I could change the portal theme and add the words DEV, QA, PRD in the mashead and show it in the portal on the top, but that would cause inconsistency, because the theme will be different for (Dev, QA, PRD). I want the theme to read the system name directly from the back end. also I am not a big fan of writing code using NWDS, so if possible please let me know how to do it in config, without writing java code.

Thanks and appreciate it; generous points for useful answers.