css styling inconsistence between wysiwyg and front-end

In wysiwyg , I configured to use theme css, but i found that the order of css files will be different between front-end and under editor. such that , editing content is not so wysiwyg .

I did a test.
Since zen_ninesixty framework has text.css, reset.css for reset and text styling say h1,....h6, ol,ul, and I have my own text styling css html-elements.css, then I remove text.css and reset.css in my theme info file and flush all possible caches.

I digged in the source, text.css and reset.css are not included. However, the editor didn't use the html-elements.css for styling but using web browser default css ( I guess). I scroll down to the bottom of the css panel of firebug, and cannot find html-elements.css.

I'm not sure it is a zen_ninesixty problem or something else.