A browser^, at a minimum, should support HTML + CSS (+1 if it supports the latest specification).
Edit: ^A modern browser
Edit: ^A modern browser
This doesn't match with current versions of accessibility software which either connects to a browser or simply bundles an embedded version of Chromium. The ship has sailed on no-JS websites sadly, and not supporting (substantially) all of CSS modules would simply render 90% of websites inaccessible.