URGENT: changing editor width

[mate]

I have a very narrow area for the forum as it's in a fixed width mambo site.

I can't for the life of me figure out where the width for the editor is set.  Manually changing the template for textarea to cols="25" makes no difference, and I can't work out where the settings for the subject line are. Please help - presentation to client on Tuesday and a hundred other things to work on as well...

mate. 
P.S. also the preview doesn't work.  :-(

[helenbpd]

Did you already change it in style.css  ?

.editor
{
width: 100%(or desired value);
}