index.html

<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>Tetris</title>
  <link rel="stylesheet" href="css/main.css">
  <script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/3.1.1/jquery.min.js"></script>
  <script src="js/board.js"></script>
  <script src="js/view.js"></script>
  <script src="js/controller.js"></script>
</head>
<body>

<div class="grid-container">

  <h1>Tetris Gold Edition</h1>

  <div class="controls">
    <h2>Controls</h2>
    <ul>
      <li>Use arrow keys to move a piece left, right, or to drop down faster.</li>
      <li>Press "Z" to flip a piece counterclockwise.</li>
      <li>Press "X" to flip a piece clockwise.</li>
    </ul>
  </div>

  <div class="score">
    <h2>Score</h2>
    <p>0</p>
  </div>

  <div class="grid">
    <div id="message">
      <p>Select initial difficulty!</p>
      <p>
        <select id="initDiff" class="dropdown">
          <option value="1">1</option>
          <option value="2">2</option>
          <option value="3">3</option>
          <option value="4">4</option>
          <option value="5" selected>5</option>
          <option value="6">6</option>
          <option value="7">7</option>
          <option value="8">8</option>
          <option value="9">9</option>
        </select>
      </p>
      <p>
        <button id="play-button" class="btn">Let's Play Some Tetris!</button>
      </p>
    </div>
  </div>

</div>

</body>
</html>