LOL
I don't use MySpace, so I could be talking out my arse. But, I understand they have different skins to choose from, and you can do further customization from there? I'm assuming the skins each call on CSS files. The CSS files define pretty much everything but the actual text and image sources on the page. I'm not sure if adding HTML tags will override the CSS or not. My guess is not since the standard has moved away from HTML and no longer accepts many attributes and tags like the <font> tag (though browsers still render it just fine).
So what you really need is the CSS file(s) that your page is calling on to define all the formatting and design. The HTML is only defining the actual content of the page.
For example, here is a web page I made the other day. It's very sparce right now since I just threw it out there after a few minutes of tweaking:
Kennel van Kelder
Now, here is the same page again, but only the HTML code, the ONLY thing removed from the source code of the index.html file is the reference to the CSS file:
Kennel van Kelder
There you can see how the CSS controls everything BUT the content of the page.
I don't know if that's how MySpace works or not, but if you are seeing references to CSS in the source code, you probably need to edit the CSS to control the design of the page.