Changing Text Color in MailChimp Form

Hello!

I am trying to change the text color on the unsubscribe link in a MailChimp form. I tried using the following css code in my child theme:

#mc_unsub_link {font-size: 11px; color: #a6a6a6 !important;}

The font size will change, but the color will not! Can you help?

Many Thanks!