Where will u mention Themes for the Pages and for the Application?
For pages We can instantly change the appearance of a page without changing the style of each server control on the page. From within the Page directive, we simply apply an ASP.NET theme that we have either built or downloaded from the Internet. Ex For Applications If we specify the theme in the Web.config file, we don’t need to define the theme again in the Page directive of our ASP.NET pages. This theme is applied automatically to each and every page within our application.