🧩 Interface Overview

This online Mini Sudoku Puzzle is an interactive web-based version of the classic logic game, designed with a clean, responsive interface and customizable options. Players can choose between 4×4 and 6×6 grids and adjust the difficulty level to match their skill. The game features a timer, mistake counter, hints, and dark mode, offering both challenge and convenience. With dynamic puzzle generation and instant feedback, it serves as an engaging way to sharpen logic and problem-solving skills.

Here’s what each part does:

🏠 Header Section

Title: Displays “Mini Sudoku”.
Timer: Shows elapsed time (`00:00`) with a ▶️ / ⏸️ button to start or pause the timer.
Mistakes Counter: Shows how many mistakes you’ve made (e.g., `0/3`).

Dimension Dropdown: Choose between 4×4 or 6×6 Sudoku grids.
Difficulty Dropdown: Choose puzzle difficulty — Easy, Medium, or Hard.

*Higher difficulty means more cells are removed (fewer clues).

🎮 Game Grid (Sudoku Board)

The main playing area is a grid:

4×4 Sudoku → 16 cells (2×2 boxes).
6×6 Sudoku → 36 cells (2×3 boxes).
 Each cell is clickable.
Preset cells (given numbers) are shaded grey.
Empty cells are white — you can fill them.
The currently selected cell is highlighted.
 If you make a wrong move, the cell flashes red (error) and your mistake count increases.

 ⌨️ Virtual Keyboard

Located next to the grid:

Buttons labeled 1–6 (only valid numbers are enabled).
 A Clear button to erase a cell’s value.
You can also type numbers directly from your keyboard.

⚙️ Control Buttons

Below the grid:

1. Hint (3 left) – fills one random empty cell correctly (max 3 hints).
2. New Game – restarts with new random puzzle.
3. Download PDF – captures the current Sudoku board as a PDF image.

🌙 Theme Toggle

 The 🌓 button in the top-right corner toggles between **light  and dark mode.

🏆 Pop-ups 

Two possible game-end popups:

Win Message: “🎉 Congratulations!” — shows your final time.
Loss Message: “😞 Game Over!” — appears after 3 mistakes.
Each Pop up lets you start a new game.

🧠 How to Play & Solve

Step-by-Step:

1. Choose puzzle size and difficulty

Select 4×4 or 6×6 and desired difficulty(Easy, Medium, Hard).

2. Start the timer

Click the ▶️ button to begin playing.
The timer starts counting, and your score gradually decreases over time.

3. Select a cell

Click any empty white cell on the grid.
The cell gets highlighted.

4. Enter a number

Either click a number button on the virtual keyboard or press the corresponding number on your keyboard.
The number appears in the cell.

5. Check for correctness

If the number is correct → stays and your score increases slightly.
If wrong → cell flashes red, your mistake counter increases, and your score decreases.

6. Use hints (optional)

Each hint automatically fills one correct cell.
You only get 3 hints per game.

7. Win or lose

Win: When all cells are correctly filled.
Lose: After 3 mistakes — the “Game Over” message appears.

8. Save your puzzle (optional)

Click Download PDF to save the current Sudoku layout as a `.pdf`.

🔧 Behind the Scenes (Logic Summary)

✅ Puzzle Generation

The `SudokuVariant` class creates a fully solved board, then removes numbers based on difficulty:

Easy → remove ~30–35%
Medium → ~40–45%
Hard → ~50–55%

🔍 Validation Rules

The solver enforces Sudoku rules:

Each row must have all numbers once.
Each column must have all numbers once.
Each subgrid (2×2 for 4×4, 2×3 for 6×6) must have all numbers once.

⏱️ Timer

Every second, your time increases.

💡Strategy for Solving

When playing manually:

1. Scan rows and columns to see where numbers can go.
2. Use elimination: If a number already exists in a row/column/subgrid, eliminate that possibility.
3. Use logic, not guessing.
4. If stuck, use a hint to reveal a clue.
5. Keep an eye on the mistake counter — 3 wrong moves end the game.

In summary, this online Mini Sudoku Puzzle combines entertainment and mental exercise within an elegant, user-friendly interface. Its adaptable features—such as difficulty settings, hints, and downloadable puzzles—make it suitable for both beginners and experienced players. By integrating smooth functionality with thoughtful design, the game provides an enjoyable digital experience that keeps players thinking critically while having fun.