Show HN: Pure CSS Connect 4

CSS is so weird.

On one hand people can do absurdly amazing things like this, and on the other I am sitting here trying to line up baselines of two text elements that are in different parts of the layout and I want to just throw my computer out the window.

I wonder if this code has been generated in part- it seems like one hell of a hassle to figure out and write by hand... But holy cow, it's awesome!