CSS Only Sudoku

Easy Sudoku

Medium Sudoku

Hard Sudoku

About

About CSS Only Sudoku

CSS Only Sudoku

This is a fully functional Sudoku game built entirely with HTML and CSS. NO JavaScript was used.

How It Works

The game uses clever CSS selectors and the :checked pseudo-class on radio inputs to track game state. Pure CSS logic validates moves and detects winning conditions.

How to Play

Click on any empty square to open the number picker
Select a number from 1-9 (or X to clear)
Invalid moves turn squares dark red
Complete the grid to win and see confetti!

Rules

Each row must contain numbers 1-9
Each column must contain numbers 1-9
Each 3×3 box must contain numbers 1-9

Created by @whosmatu

View source on GitHub