Foodoholic free looks strange in live preview

Hey there, I hope you're all fine! I am still trying to fix this issue but I HAVE REALLY NO IDEA! When I activate the live preview of Foodoholic free on my website there it is like a dark layer over the page. Where can I change / fix this? If possible, I would open a new role that you could go in the website control panel. Best wishes and thanks in advance for your help! Natalie