Change color to prevent visibility issue

I can't replicate it, but I think the issue is that the caption seems to appear in a lower area of the image on some screens so that the brown font blends into the brown background.

I changed it to a lighter font when the image is shown so that the caption should appear well in both the light and dark areas of the image.

Also changed the coloring in hover to make it flow more naturally and removed extra px designation and space.