Hi,
Yes, add a css style sheet with all your main default styles, text color, size, heading, links, body background of what their content area background will be. Call it cms_mystyle.css or whatever you want, save it into the HTMLEditor/custom folder, then add the link to it at the bottom of contents_insert_ContentValue1.js and the contents_update_ContentValue1.js
The headings tags will show up with the css formating in the font format dropdown and all the other styles will show on the page as they add content or choose lists etc... If you want them to be able to choose styles and for them to show in the styles dropdown, you will have to add those to the xml file.
FCKConfig.EditorAreaCSS = '../custom/cms_mystyle.css'; // relative to fckeditor/editor/fckeditor.html
FCKConfig.BodyClass = '';
FCKConfig.StylesXmlPath = '../custom/contents_insert_ContentValueStyles1.xml'; // relative to fckeditor/editor/fckeditor.html
FCKConfig.ManagerEnabled = true;
if (true) {FCKConfig.Plugins.Add('kfm');}
Hope that helps,
Gerlinda