Tic Tac Toe Redesigned with Material 3 Expressive

The Tic Tac Toe game has been redesigned with Material 3 Expressive design, featuring indigo/blue gradients (#5c6bc0 → #7986cb) for Player X and red gradients for Player O, 28px rounded game board with gradient cells, M3-styled toggle buttons for difficulty and starting player selection, polished score and turn indicator chips, and enhanced win/draw alerts with gradient styling.