I have written this code to get a 600*600 canvas but something is wrong please help. this is the git link for both HTML and Js code.LINK

const BG_COLOR = "#231f20";
const SNAKE_COLOR = "#c2c2c2";
const FOOD_COLOR = "#e66916";

const gameScreen = document.getElementById('gameScreen');
let canvas, ctx;

function init() {
  canvas = document.getElementById('canvas');
  ctx = canvas.getContext('2d');

  canvas.width = canvas.height = 600;
  ctx.fillStyle = BG_COLOR;
  ctx.fillRect(0, 0, canvas.width, canvas.height);

  document.addEventListener("keydown", keydown);
}

function keydown(e) {
  console.log(e.keyCode);
}

init();