A style sheet CSS file is a text file. As such it can be opened using notepad. Alternatively a graphical editor such as Microsoft FrontPage or Microsoft Visual Studio could be used. If a graphical editor is not available the following web page may prove useful in providing examples of color and codes for use in setting the scheme settings.
"Colors by saturation" document on Microsoft website:
http://msdn.microsoft.com/library/default.asp?url=/library/en-us/dnwebgen/html/X11_sat.asp