I've just posted a step by step guide on integrating FCKEditor with your site CSS styles over at nmglc.

Quite a few of my smaller sideline projects and client work involve low cost CMS-type solutions using PHP and various free and OSS packages.  For simple CMS jobs, whether I'm using Drupal or rolling my own, I use FCKEditor for WYSIWYG editing these days.  FCKEditor scores over my previous favourite, TinyMCE, because it has server-side file and image browsing capabilities out of the box.

One thing I had not looked into in much depth before was how to get the editor working smoothly with a site's CSS rules.  The default way of working in FCK seems to be to set up choosable styles that apply inline styles to various elements, or insert block elements into the content.  I wanted to be able to have it link to the site's style rules so that if these were later updated, the content would be consistent with the new CSS.  It turns out this is pretty easy, so I thought I'd outline the steps involved in case anyone else might find it useful.

Link to article: nmglc.co.uk/content/simple-fckeditor-css-integration