Change text and highlight color of caption

First, a question. When I am editing the settings of my gallery, the caption text color is white. However, when I view it on my page, the text color is black.

I’d like to it be white. So what I’d like help with is either a) figuring out why the color is changing, or b) creating a custom css code to manually change the text color.

This is the page: https://www.pepwear.com/design-gallery_test
The gallery I’m referring to is the second one on the page.

Thank you!