Change background color for cacti

[virus84]

Hello

I have managed to change the color for the graphs so it´s black for better contrast. Is there any way to change the rest of the white background to black?
I have looked in main.css but if i change the body bg color to #000000 it only changes the boarder not the graph presentation area / tree view.
Any sugestions would be appriciated.

Thanks in advance

Regards
Magnus