Shipped this project!
i built a responsive chess web game using HTML,CSS and javascript .it includes a lobby screen ,settings (side /sound/suggestion/timer),full chess rules (castling,en passant ,promotion) ,move history,captured piece tracking ,draw claims(50-move and threefold) and PGN download, i also added desktop drag-and-drop plus custom mobile touch-drag with a floating piece preview game play ,the hardest part is handling legal move validation while keep the king safety checks accurate