Change title position gallery grid lightbox view

Site URL: https://parrotfish-harmonica-7ta6.squarespace.com/config/design

Hello,

I have been trying and trying to change this with a variety of code and trial and error and I can't make it work - I am new to this so still learning.

I thought I had cracked it, then when I refreshed it just reverted back to a version of the same

- I want to move my title to underneath the image

- change text to black

- remove grey transparency box

Can anyone help me do this - it is the lightbox pop up on a gallery page

Thanks so much