product image black when opening lightbox

Hello,

We have analyzed your website, and it seems that we have element about your current issue, see my screenshot :

In details, remove an inline css commande (or override it thanks to a stronger priority css command) seems to be a possible solution.
But I wonder if your issue isn't link to your current template... And so, can you process a test with a default template like Protostar ?
Awaiting your returns to better answer to your issue.

Regards