For one, all styles must be inline. Most mail clients do not support stylesheets.
You are not building a web page, you're building an email, therefore everything in your HEAD section will be removed, including your embedded stylesheet.
In you code you have </br>
. This is not a valid tag. Use <br />
.
NEVER NEVER use !important
. Inline styles already override other styles, plus you can dig yourself into a dead end.
Put your text in a DIV or a P and style that, not the TD. Not all styles are supported by every mail client. Here's a good list to compare to.