-Styles must be improved (full width for smartphones, ...)
-PGN text is not selectable (understand why?!)
-Change cursor when computer "think" (sablier)
-Tooltip text should fade (even when mouse stay on it, especially for small screens)
-Checkered stage 2: switch button at reserve position (or on top).
-Mode expert: game.js, button on top (with online indicator)
-Turn indicator on top too (black or white)
+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