Why Did My Font Change to White with Black Outline?

I have a Nexus 5 running Lollipop. One day I picked up my phone and my font was changed to white with black outline. I have developer options enabled but even so, I cannot change the font at all, which is why it is so weird that my font was able to be changed. I would like to change my font back to the factory default. Any help would be greatly appreciated.