I won't be able to test this until later today since my device isn't with me, but I've made the needed updates to my IT. (Having SSH access rocks. )
I needed to create the chrome folder in the /home/user/.mozilla/microb/ and then create the new file, userContent.css

I created both as root however, so I'm guessing that the permissions should be changed in order for this to work.

chown user chrome; chgrp users chrome
cd chrome
chown user userContent.css; chgrp users userContent.css