Activating popup from CTA button on Salient theme

Hello!

Like the title says I am attempting to activate a pop up with the plugin when clicking the CTA button on the Salient theme.

The button can be seen here http://filmsta.sh/resources/no-film-school/ near the bottom in red. When I attempt to edit the footer.php file and add in the class of the button I am able to get the pop up to trigger but then it overrides the css of the button and it changes color and style.

Any help would be appreciate!

Thanks