I think this is something browsers should enforce. Different people may have different preferences for what they consider comfortable contrast ratios, and the t

I think this is something browsers should enforce. Different people may have different preferences for what they consider comfortable contrast ratios, and the tool in the stack that directly serves the user, is the browser. And even if websites should consider proper design, browsers should also enforce user preferences, because badly designed websites will probably always exist. I'd suggest browsers come out of the box with a decent contrast range that they will use to display text, but users should be able to modify those settings. In general, browsers should be a lot more willing to override bad webdesign ideas. They already block popups and blink tags; there's plenty of other behaviour they simply shouldn't tolerate from websites.