Mail module: font very small in Outlook

I've had users of Outlook complain that the HTML formatted mail they recieve uses a very very small font. One told me he had to export the mail to word, then zoom 200% just to read it.

I realize this may be a function of the theme I'm using (based on Kubrick). And I'm sure the blame lands squarely on Microsoft's shoulders. I don't know why anyone would use their crappy email client but since just about everyone does, its important to work with it.

I hope to do some more investigating. Not sure how, since I don't have Outlook. But I just wanted to post this in case anyone else has run into the issue. If I find out more, I will follow up.