-Styles must be improved (full width for smartphones, selectable text for PGN...)
-Tooltip text should fade (even when mouse stay on it, especially for small screens)
-Checkered stage 2: switch button at reserve position.
-If a played disconnect right after opponent sent a move, it might be never received: secure this
-Think about non-conventional variants with 2 kings for example: undercheck highlight?
- --> underCheck should return a vector in this case. Adapt.
- --> incheck should be an array of squares, in general. Think AntiKing
+For animation, moves should contains "moving" and "fading" maybe...