You can’t change the colors of the icons or images with CSS. You need to manipulate them in some graphics package like Photoshop, Fireworks, Corel Paintshop Pro or some free ones available online.
CSS is mainly for text and layout stuff.
I have photoshop that I can change the colour in but where can I find the icon in the first place? The only place I can find any reference to the icon is Theme > Social Media Options > Icon Link, and all I can do there is paste the web page link.
Any ideas as I have a white icon on an off white background?!