Created by: ffoodd
Fixes #34732 (closed), closes #34764 as a replacement, basically refactoring the evolution from v4 instead of adding old code.
The main culprit here is getting back to a 2px border, since for whatever reason a 1px border is hidden behind cells borders. As pointed out by @adityadees, a 1.1 multiplicator would be enough, but feels like a magic number to me.
IMHO @mdo we'd better recommend to use our border utilities (eg. .border-dark in the initial issue, as in this dedicated CodePen) rather than fixing this. Any thought?
Demo on CodePen.