change two colors in css – where to find

I was once able to change two colors by going into the CSS of the plug in – the bar that separates listings (#0c508b), and the gray field headings on a listing (#333). The plug in has since been reset to the default and I can’t find these two codes again. The colors are very hard to read with our site theme. Where can I find these colors to change them to white?

Thanks!