Green Color blocks

[wcchew]

Hi guys, i'm pretty new to CSS and all, so please be patience with me.
Have done my fair-share of searcing and trial and error, but i simply could not change the background color and the "dirty" green headers (not sure what i should refer them to).
Have been tweaking the /templates/classic/css/stylesheet.css.
i can actually see the change in the headers but it is overwritten when the page is finished loading again. (as in initially loaded the right color, then , opps, covered by that "dirty" green again.)
Wat could be wrong?
thanks all in advance..

[karen]

I think the green comes from an image.