Change background behind three-column and feature areas

I changed the "body" background and that worked, but the area behind the three-column feature area and other feature areas is still white. I would like to change that to black. Can you help?

 

Hello,

Paste the code given below in Custom CSS section
(Appearance -> Theme Options -> Styling Options -> Custom CSS) of your dashboard.

Code:

.content-container {
  background: #000;
}

Thanks & Regards
Pramod Patel