index.html

<!DOCTYPE html>
<html lang="en">
<head>
      <meta charset="UTF-8">
      <meta name="viewport" content="width=device-width, initial-scale=1.0">
      <title>Sumon Game</title>
      <link rel="stylesheet" href="./style.css">
</head>
<body>
      <h1>Simon Says Game</h1>
      <h2>Press any key to start the game</h2>
      <div class="btn-container">
            <div class="line-one">
                  <div class="btn red" type="button" id="red"></div>
                  <div class="btn yellow" type="button" id="yellow"></div>
            </div>
            <div class="line-one">
                  <div class="btn green" type="button" id="green"></div>
                  <div class="btn purple" type="button" id="purple"></div>
            </div>
      </div>
      <script src="./app.js"></script>
</body>
</html>