I've been asked to apply a change to the background of our website at work. However I need to be able to test it before I put it live and I need to test it on the test site. However if I make a change to css it applies it instantly to live and the test site. This is not good for customers if the background of the website is constantly changing colour and potentially presenting incorrectly.

Is there anyway I can set a piece of css to only apply if jquery has checked the url in the browser and if it matches that of the test url I query it with. Then it will only display the css I've written for the test site?