Caption Font Color in Single Image View

I am having trouble with the font color of my captions when viewing a single image in my image gallery. When selecting the gallery project and subsequently see the full gallery, the caption font is white on the dark background which is what I want, however, when clicking on an individual image, the caption font color is black and naturally you can hardly see it.

I don't seem to be able to find a way of chaging this to white so are looking for some help.

https://www.petercoxphotography.com/gallery/project-one-6k5lj?itemId=d98dmzwr55c00m209zzubo4we3xq1c

Thanks Peter

Hello, try adding this to Custom CSS:

.tlightbox-caption {
  color:#fff;
}
.gallery-lightbox-background {
    opacity: 0.96;
}

Hope that helps!