Lightbox issues - not mobile responsive and caption cuts off

Hello, I’m having some issues while creating a gallery page using lightbox with captions.
All the images are square and in a grid and the gallery is responsive and that’s all fine. I added a lightbox to these images with a captions for each of them.

Problem 1: When the caption is longer than the width of the image it gets cut off. Is there a fix to this?
Problem 2 (main issue): When viewing the lightbox on mobile it’s not responsive. See screenshots:

Anyone else have this problem?

@Kat96

Please add your share link so the community can actually help.