The textfield issue is being worked out in bug 227135, but the contrast of checkboxes and other controls are still using -apple-system-opaque-fill rather than -apple-system-opaque-separator or another more appropriate and higher contrast system color.
The extreme low contrast problem was called out today in https://twitter.com/gerireid/status/1405203573269569538
Created attachment 433160 [details]
Comment on attachment 433160 [details]
View in context: https://bugs.webkit.org/attachment.cgi?id=433160&action=review
Nit - you could probably pull `checkboxRadioBackgroundColor(controlStates, styleColorOptions)` out into a local variable here to avoid writing it out twice.
> + context.setFillColor(checkboxRadioBackgroundColor(controlStates, styleColorOptions));
Created attachment 433229 [details]
Patch for landing
Committed r279795 (239562@main): <https://commits.webkit.org/239562@main>
All reviewed patches have been landed. Closing bug and clearing flags on attachment 433229 [details].