find the ckeditor.css/editor.css template and hardcode the changes.
--------------- Added 25 Jun 2011 at 21:29 ---------------
found another thread that covered this
the easiest way is to add the following to your additional.css template
Code:
/* Background Color for CKEditor */
.cke_skin_kama .cke_wrapper {
background-color:#666666!important; }
/* Background Color for CKEditor - END */
changing the hex code # above to whatever color you want
though with all you want to change it might be best for you to go to your server side cPanel>File Manager and edit the following file: root>clientscrip>ckeditor>skins>kama>mainui.css
and for the toolbar/tool icons same place but the toolbar.css