I'm posting a revised version of my site. Most of the text and background colors are governed by css. some of the background colors for divs, tables, cells, etc. is that same as some of the text in the site, but i'm not hiding any text (all appearances of light text is on a dark background). Can i be penalized for just having some backgrounds and text the same color even it they are never used together to hide text? Can search engines see my css file. If so, can i hide it with a robot.txt? If i change the text and bg colors very slightly, am i still at risk?