Ignoring substring matching attribute selectors

I am trying to apply css to any table row with a class of component-type-commerce-coupon-*. For example, it could be component-type-commerce-coupon-pct-vegas or component-type-commerce-coupon-pct-newyork.

According to CSS3 Substring Matching Attribute Selectors, I can match a substring with a selector. I can add tr[class*="component-type-commerce-coupon"] to my regular css and it does indeed affect those rows.

However, when I add that same selector to my mail.css, Mimemail seems to ignore it. I am assuming this is a bug?