header content on homepage lightbox gallery

Site URL: https://www.iamdelsingh.com/

I noticed that if you click on an image on my homepage then a lightbox slideshow pops up. What I don't understand is that the header content appears. I can't edit the gallery to remove the header content or even disable the slideshow. Do you know why this is the case? In the end, I'd like to remove the header content only when the lightbox slideshow appears after clicking on an image in the homepage. In addition, there isn't a way to edit the lightbox gallery.