New post/quick reply colour question

[jmarellano]

This is probably really simple, but I can't seem to find out what template to edit, but how would I go about adding colour to the standard editor? I don't want it to be WYSIWYG, though I also don't want the box to be white like the attachahed image.

I'd like to change the colour of both the new topic/reply and also the quick reply boxes. So yeah, what template and what part of them do I edit?

Thanks.