Changing Colors on middle and side column

[dragoncelt]

How do I change these background column colors from white to black?

[kuroi]

Just add the following to your stylesheet

#contentMainWrapper {background-color: black}

[dragoncelt]

Which style sheet in which file?Sorry but I'm new at this.

[kuroi]

If you're using a recent version of Zen Cart and aren't using a 3rd party template, it would be the stylesheet.css file in your templates css folder.