How to change Product Reviews font color?

[SaraRosalie]

I just installed the Product Reviews app, and so far so good. It's just that some of the text when opening the field of 'add your review' is either transparent or in the same color as the background. 

Does anyone know how to adjust the color of this text? Here live: https://sararosalie.nl/products/eye-balm (click on 'schrijf een review').

You have to go over the page and select to see the text I'm talking about.