I think this is a good example of what CSS can do and probably was not easy to make but I will likely stick with Mahjong that comes with most Linux distributions as they follow rules that people I may end up playing against would know and they have many layouts. I could see this being applied to other things however such as games that require building or repairing something. Or something similar to Minecraft?
Impressive work!
I wonder if versus Mahjong Solitaire could be like Battle Tetris. I've never heard of people playing it competitively.
Minecraft in CSS has been done, actually! https://benjaminaster.com/css-minecraft/
Discussion: https://news.ycombinator.com/item?id=44100148