How do you change the font color of icons on the launch screen?

I've changed all the "color" fields' color in the ".../stylesheets/photos.css" and nothing appears to have changed. I have a background with a lot of white/light coloration and the "wallapaer," "all images" etc. fonts are in white and difficult read. "appinfo.json" didn't help either. Where do I change the font color for this?

Thanks