-Finish rules translation in Spanish
-Design: final touch (gain extra space on top, using space on the right)
-Crazyhouse: center reserves, grey if zero available, numbers superimposed
+Checkered chess: need another FEN element, last non-capturing checkered move (if applicable)
+ + need to stack these indicators for alpha beta search
+MarseilleChess: revise bot and test
+Translations (including About page), refresh rules