Oh, sorry, I missed that part in your question. I think you have to search for the .css files located within the themes folders and its sub folders. You can get the name of the theme you use, and by using the name you can easy get the root path to the theme folder. What you have to do after that is to find all the .css files you have added to the theme folder.
string themePath = Request.ApplicationPath + "/App_Themes/" + Page.Theme;
/Fredrik Norm?n NSQUARED2
Microsoft MVP, MCSD, MCAD, MCT
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