Affiliates Shortcode Custom CSS

I'm trying to style the affiliates message on my Membership 2 Account page.

I've added the following shortcodes to the Upfront Text Box on my Account page:

I was able to style the ms-membership-account table fairly well on my own, but I'm struggling with the format of the Afilliate styling.

1. Is there a CSS example I can see?
2. I can't get the background color to change to yellow like the user guide shows

Thank you,