Hey Is having a background still legal for adsense ads? or no Check out some examples here http://adsensebackgrounds.com/ Thanks Tyler
I'm sure it is allowed as I've seen it before, but I don't think they look pretty...or that they improve clicks..
some of them are not allowed. example: placing and image close to the ad block to catch attention is not allowed. also, if someone from adsense team comes to review your site you will definitely get banned because to them it will obvious that you made those CSS tricks to make the ads more attractive.