Fix focus styles across browsers #451
Description
In Firefox, we see very little visible focus. This is pretty unusable. In Chrome, we have vastly more usable focus indicators, but most are not styled the way we want.
Using :focus-visible to make focus indicators show up only during keyboard nav and not, e.g., when the user clicks a link would be perfect... if it worked in Safari. We could use a hook that would let us do our own version of this at the application level to make it work in Safari. That may or may not be worth the effort at this point.
Keyboard nav in Firefox
Keyboard nav in Chrome
