Change Font Size & Color

Hello,
Im using this plugin to display a message to customers. I wanted to make it a little larger, and change the font color to make it more noticeable to customers. I haven’t figured out how to do that. I’ve tried adding simple things like <font size=”24″> but this doesn’t seem to work. Please let me know if there is another way to do this.
Thanks

The page I need help with: [log in to see the link]