Increase top value to lightbox Element

Hi awesome developers,

When using the lightbox feature, the image shown starting from the top of the page.
However, I have a sticky header which covers the top part of the iamge lightbox.

After checking the css, the “top” for element #Lightbox is 50.
How can I add 150 to the original top value? (Or make sure the lightbox image pops out in the center of screen)

I tried to hardcode the top value to 200, and it only works on the 1st row of images. Because the top value for element #Lightbox changes depends on the row of the images.

Image issue : https://ibb.co/xHF73Zh

Thank you in advance! 🙂

The page I need help with: [log in to see the link]