Different colors for individual posts

Hi, thanks for this wonderful theme. I’m a total newbie and english is not my main language, sorry if I’m not very agile.

I’ve been trying to change the background colors of individual posts. There seem to be different plugins to do that, but for some reason they are not working for me. To make clear what color I mean, it’s the one you can change in Theme Options / Design / Content Background Color. Only I would want to chose for each different post.

Is there any way to do this?

Thanks so much.