For additional theme change articles, see the below.
Solitaire
How Do I Change My Theme to Dark?
Is there large text card option (Jumbo)?
Mahjong
How do I change the tile size?
How Do I Change My Theme to Dark?
How do I change the Theme in Mahjong by Microsoft?
Sudoku
How Do I Change My Theme to Dark?
How do I change my Theme in Microsoft Sudoku?