Snake

Build a playable Snake game on a canvas with a 20 by 20 cell board. Use HTML, CSS, and JavaScript as needed. Write it to `index.html` in the current working directory using your file tools. Inline your own CSS and JavaScript. Do not use external assets, CDNs, or network requests. No third-party libraries are provided. Required behavior: - Use arrow keys to turn a snake that advances one cell at a time. Ignore a direction that would immediately reverse into its own neck, including rapid inputs before the next movement step. - Place one food item in an unoccupied cell. Eating it grows the snake by one segment, increases the score, and spawns new food in another unoccupied cell. - Use solid board boundaries: hitting a wall or the snake's body ends the game. Moving into a tail cell that vacates on that same non-growing step is allowed. - Provide Start, Pause/Resume, and Restart. Restart resets snake length, direction, score, food, and game state. Filling the board shows a win state instead of trying to place impossible food. - Display the controls and score. Prevent arrow keys from scrolling the page. Verify: Start the game and make a few turns to check grid-aligned movement and direction response. Pause and resume, then use Restart and check that snake length and score return to their initial values and food occupies a free cell.