Reader view defaults to low contrast text, but it's possible to set your own text colors with custom userContent.css:

https://news.ycombinator.com/item?id=15080363

THANK YOU!!!! You have solved a problem for me today and I am very grateful. :-D

Seriously: I am so happy. This is one of those little things that is going to keep me grinning all day. Thank you so much for figuring this out and posting it.