I strongly agree with contrast rebellion. Having said that, a bright white background and black text is harder for me to read than a light grey background and blacktext.
But the back ground shouldn't be darker than #cccccc
I think, but I do not know, that some people with Aspergers prefer a lower contrast. (See, for example, early websites using silver background with black text.)
Yes on the contrast. RR does a dark-on-beige scheme on its rendered pages by default. I use MoonReader+ as a eBook reader on Android, it does similarly.
There was some research in the 1970s or 1980s about maximum readability for paper texts which arrived at similar conclusions. A dark brown text on matte cream paper tested best. I've read several books printed in this format, and found it quite readable. Though paper still beats screen for readability (but not grepping).
But the back ground shouldn't be darker than #cccccc
I think, but I do not know, that some people with Aspergers prefer a lower contrast. (See, for example, early websites using silver background with black text.)