Hello,
Currently, there is no such feature in our theme. But you are right, we are using Magnific popup in our theme and so we will consider introducing some general popup shortcode in the future. At the moment, you may try create it yourself. Just find necessary example in this plugin documentation and use it. You can add extra JS code to the Custom JS section in Theme Settings. http://dimsemenov.com/plugins/magnific-popup/documentation.html
Regards