Sudoku: styled brain game

There are minimalistic monochrome styles and colorful styles which children like.

There is no some extra gameplay functions like hints, undo and redo steps, custom grids etc. Just classic game with base functionality.

Features:
- 5 Different themes with sub styles (Classic with colors, Tiles, Xmas, Marbles, Cartoon and more themes in the future)
- The game is completely ad-free
- 4 difficulty levels of sudoku
- Auto saving your game progress
- Pencil marks
- Highlighting conflicting cells and same digits (you can setup this)
- There is no night mode, but you can choose one of dark themes

If you have some ideas for new sudoku board styles or improvements to the game, let me know. Perhaps your idea will be implamented in the next update.