Add space between button and input

Hello everyone,

I read in this page of Wysija’s support how remove the space between input and button.
.wysija-submit-field { margin-top:0 !important; }
i added in my code this line
.wysija-submit-field { margin-top:10px !important; }
to add space between button and input but didn’t work :s
any suggestions please

http://wordpress.org/extend/plugins/wysija-newsletters/