color management and customization

How do I work with the colors and customize the look of my email. I'm using Mozilla Thunderbird, but I'm open to using a different email program if it's required to create better styles and themes when sending email.

Does this guide to using stationery in Thunderbird help to solve the problem?

How to get stationary in Mozilla Thunderbird | Email Questions

There are also style options available as a toolbar if you are not sending plain text email: