Product Background Color. Please Help!

Hello, I can't seem to change the background color of the products window. When I try to discover what .css file drives this, I get 'NULL' Please see below images.

The only thing I can find is in SYSTEM>CONFIGURATION>DISPLAY (as show in bottom image) but it won't actually update the color.

Please help!

Solved, whew...that one took a while.

I really hope there is an easier solution than this for other people....

/media/com_hikashop/css/frontend_default.css

The default parameters are default values for new modules and menus.
For existing modules and menus, you need to go in the menu Display->Content menus/modules and edit your menus/modules' options and set the background color there. No need to change the CSS for that.
Also, when you modify the CSS, you should do it via the Display tab of the configuration. If you do it directly in the CSS file via FTP, you will loose your modification when you update HikaShop.

Thanks for the tips.