How do you change the visual editor’s background color?

I have a WordPress site in which the background color is black and the text is white. The site is fine, but it’s a pain trying to edit content in the visual editor as the background is white (same color as the text). I end up having to tell users to use the HTML view or write up the content in black color text and then at the end just select all the text and flip it to white (in which case many of them freak out and think their text is now deleted!)

How do I change the background color of the editor to black (or any other color) so that the content can be readable if the text color is to be white?

similar to the answer by GavinR, using the wordpress add_editor_style() function; (as implemented in Twenty Ten and Twenty Eleven)

in functions.php of your theme, add:

add_editor_style();

then create an editor-style.css in your theme folder:

.mceContentBody.wp-editor {     
  background-color: #000;
  color: #fff; 
}