something that's always confused me about DNN.....

there are layers of style sheets and yet the interface only exposes ONE stylesheet for editing. why is that? the stylesheet which is exposed only exposes a few of the elements needed to truely have control over the look and feel. and the other stylesheets are buried in folders which are not exposed by the admin or the host account's file manager. i've quite understood how the admin and host file managers determined the level of folders to expose. it would be great if it truely exposed ALL files and folders under the root. but instead....it's a small subset.

for example.....i don't see any way to alter the color of the menu items in the default setup. this is because the setting for the menu items is in a stylesheet which can not be accessed by the dnn interface.

why is this?

AFAIK, correct order is

1. Default.CSS
2. Module.CSS
3. Skin.CSS
4. Container.CSS
5. Portal.CSS

details can be found in Skinning guide.

You can make all changes in portal.css simply by overwriting the CSS that's in the other CSS files.

Also since DNN is a multi portal system. Allowing an admin to edit the css of a skin might influence other portals that use that same skin.

That's what portal.css is for, it's portal specific, while a skin is not (always)