Subjective though it may be, there are a lot of people who find black-on-white unpleasant to look at. I greatly prefer sites that don't use it, regardless of what they do with font and size. This could just be a case of conflicting preferences, but I don't think it has to be. Clear contrasts are achievable without insisting on #000/#FFF web design. - The most obvious improvement is simply keeping an eye on contrast.…
Shifting the background colour, slightly , tends to be vastly more readable than screwing with the foreground colour: https://codepen.io/dredmorbius/full/KpMqqB/ It also far more closely approaches the appearance of print on somewhat aged paper: https://archive.org/stream/commercialismjou00holtuoft#page/5...
#16110b and #e3d2ae for text and background.
I might just use that in future websites.