Doing this in CSS could take a long time, but it is possible as it is basically a decision tree. Not fully completing the challenge, but related to it: here is a CSS-only Connect Four:
Nice ! This is a very creative way to solve the problem.
Are you sure you want to hide this comment? It will become hidden in your post, but will still be visible via the comment's permalink.
Hide child comments as well
Confirm
For further actions, you may consider blocking this person and/or reporting abuse
We're a place where coders share, stay up-to-date and grow their careers.
Doing this in CSS could take a long time, but it is possible as it is basically a decision tree. Not fully completing the challenge, but related to it: here is a CSS-only Connect Four:
Nice ! This is a very creative way to solve the problem.