I have just spent half a day quietly going mad.
I\'m making changes to my classes in the Site.css file and they were not being reflected in the site being develope
Press CTRL+F5 to hard-refresh everything on your webpage including scripts and stylesheets.
Additionally, you can incorporate the stylesheets to be served from a dynamic server page [php/asp.net] and the Response.Expires = -1 which will force the client to load the css on every HTTP-GET request explicitly. You can also do this in your webserver settings for CSS mime types.