How to change Blogger Comment background color

Looking for a way to customize the embedded Blogger Comment text box background color for older Themes. The four newer themes Contempo, Soho, Emporio, Notable all set Comment background to match Theme colors but remove Theme Layout control.  Visitors typing new comments are stuck with the plain white comment text box. If you know how to change the white Comment text box background on this "Simple" theme please leave a comment.
thanks