It looks like you had some communication with my friend Gillian regarding your Lightbox form popping up using Safari. Just want to reply here as well so if other customers come across the same issue, they are able to search in Emma Community.
I don't think that you need a webkit as the form should work in Safari. We did some testing here at Emma with your form on your site and it pops up when using Safari. You may need to update to the latest version of Safari or there may be a plugin on the browser that is preventing the form from popping up. I would suggest looking into either updating to the most recent version of Safari or taking a look to see if there is a plugin and that will hopefully do the trick!
Feel free to reach out here with any questions or if there is anything else I can do to help.