The graphical recommendations included in this guide are game-specific. You can find general recommendations for backgrounds, logos, and other images here.
In the Sudoku game, the Sudoku grid is created in the platform, so you won't upload any graphics to the game.
In the layout settings, you can define the look and feel of the grid, including:
Font type of the numbers
Font color of the numbers
Font size of the numbers
Color of the numbers that are input
The color of the Sudoku grid
It can be a good idea to differentiate between desktop and mobile layouts for the best game experience across devices.