I usually set the body tag to have a background-image and  background-color that is dark with a color that is light.  Unfortunately that means most text editors then use the body settings in their edit text box, which blows the WYSIWYG reason for using a text editor because the edit textbox is dark, even though your contentpanel may be white/black.  In the past I always set the css file for the site that text editor used to same colors (white background, black text) that the main content area used and then linked another style sheet with the body tag set to whatever I needed.  That way the text editor would use the site style sheet for the edit textbox but the site body tag would be overridden with the second CSS file.  That doesn't seem to be possible in DNN.

I noticed the demos had the same problem with the dark background color and *think* I may have discovered a workaround.  Find the FCK Editor CSS file (ExampleSite\Providers\HtmlEditorProviders\Fck\FCKeditor\editor\css\fck_editorarea.css) and reset the background-color, background-image, and color tags so that it looks something like this.

body
{
    background-color: #ffffff;
    padding: 5px 5px 5px 5px;
    margin: 0px;
    background-image:none;
    color:black;
}

I could be fooled by a caching issue but, so far, this seems to be the solution.  I'm going to try it with the link colors next because that's the next usual issue.

Something else that might be worth noting - In the tutorial it recommends adding FCKConfig.BodyID = ‘fckbody’; (Tutorial doesn't include ";" at the end I added that after some exploration and viewing http://docs.fckeditor.net/FCKeditor...BodyClass) within providers/htmleditorProvidors/FCK/custom/fckconfig.js fiile. I found it easier to not a add a new div, I used the same div I used for the contentPanel, "content", because then I wouldn't have to also add overrides for links etc in two places and because, most of the time, those using the text editor will be using within the contentPanel.

Easiest way to keep the FCK Editor displaying the background of your contentpane while having a dark background using CSS from
"Pure CSS SEO Layouts for DotNetNuke skins". Style the body with the same background and color as your contentpane, then add real background colors/images etc to the wrap div.

Another note:  Apparently modules use the "body" settings for modules in right/left panes.  I found that setting dnn_leftpane,#dnn_rightpane with the background, color, link colors I wanted for each module in the left/right panes (in my case the dark gradation used in the #wrap div) causes each module to display using those settings without having to create different containers.