Modern Sudoku Game Development for Website

I'm in need of a game developer to create a Sudoku game (9x9 grid) for my website. The game should cater to varying difficulty levels: Easy, Medium, Hard, and Extreme.

Key features:
- A table (without borders) below the puzzle displaying numbers 1 to 9, with options for undo, hint, and solution.
- A timer positioned above the puzzle.
- An option to select a difficulty level and subsequently generate and print multiple Sudoku puzzles onto an 8.5x11 inch PDF file.
- Compatibility with both desktop and mobile browsers.
- A modern design interface.
- Daily Sudoku challenges.
- A leaderboard to track player scores.

Ideal skills and experience for this project include:
- Proficiency in game development, particularly web-based games.
- Experience in creating modern, user-friendly game interfaces.
- Knowledge in implementing features like daily challenges and leaderboards.
- Ability to ensure cross-platform compatibility.