I am trying to allow users to make selections for font, and background color and other skinnable attributes. I do not want to store a different theme file for each user. How can I edit particular properties within a skin or css file from my code behind? Want I want is to have one skin or css file that has a set of default values for a set group of properties. Then I want to store unique values for each user that would on_preinit change the theme to match the users preference for each property. The only way I can think to approach this problem is to use File IO and rewrite the css file manually. Is there another way?