I'd assumed anyone with visual impairment—but not outright blindness requiring a screen-reader—was using custom stylesheet stuff pretty much constantly all over the web. Controlling the appearance of sites client-site used to be a basic browser feature. I know that's receded into the background, but is something similar (either some accessibility feature, or a plugin) not the norm for those who need them? If not, that sucks, because control used to be so firmly on the client-side for those things and that was a good thing.