It is possible to customize email body using css?

I've tried to do this but the received email appear with no styles defined in the xhtml file.
The <m:body> tag was defined the attribute type as html and no matter how define it, the email never shows styles.

The styles that I try to use includes an image equivalent to an email title, color text and size text, its something simple, nothing extraordinary.

I appreciate your comments.

Best regards.