I think I have the answer to my question, but I just want to confirm that there isn't an easier - or better - way to do what I am working on.

I have a basic html page using all CSS. What I want to do is have the option for the user to change the color scheme of the entire page by clicking on a little color coded "changer" thingie at the top of the page. I'm looking at doing 3 different schemes right now.
So obviously I have 3 different CSS files with the appropriate color settings.

My question is this: When they click on, say, the "blue" color scheme - do I have to make a whole new set of pages for the blue scheme - or how can I load the blue CSS to the current page?

Like if my home page is index.htm, and I want the blue scheme, so I have to make a page called index_blue.htm or something. That seems rather tedious.

Is there a way to switch the color scheme without loading all new re-named pages?

This seems like something that common sense should answer for me, but I'm in a daze today.