Add transitions when revealing correctness of attempt

[korompaiistvan]

I think one very satisfying feature of the OG is the slow flip of the letter cards.
With this design, the equivalent would be the "buttons" slowly inverting.

What do you think? I'd be happy to prepare a PR some time in the coming days.

[octokatherine]

Sure! This is something I've wanted to do but haven't had time yet

[korompaiistvan]

My interest in this project has unfortunately disappeared so I won't be able to work on it