index.html

<!DOCTYPE html>
<html lang="en">
  <head>
    <meta charset="UTF-8" />
    <meta name="viewport" content="width=device-width, initial-scale=1.0" />
    <title>Document</title>
    <style>
      .p-tags {
        margin: auto;
        width: 60%;
        text-align: center;
        padding: 10px;
        background-color: rgb(227, 231, 235);
        font-size: 20px;
      }
      #time-display {
        color: black;
        font-size: 25px;
        font-weight: bold;
      }
      .btn-align {
        margin: auto;
        margin-top: 10px;
        width: 60%;
        text-align: center;
        padding: 10px;
      }
      #start-btn {
        width: 90px;
        margin-right: 20px;
      }
      #reset-btn {
        width: 90px;
        margin-left: 20px;
      }
    </style>
  </head>
  <body>
    <div class="p-tags">
      <p id="session-display">Session ends in</p>
      <p id="time-display">2:00</p>
    </div>

    <div class="btn-align">
      <input type="button" id="start-btn" value="Start" />
      <input type="button" id="reset-btn" value="Stop/Reset" />
    </div>

    <script src="./app.js"></script>
  </body>
</html>