index.html

<!DOCTYPE html>
<html>

  <head>
    <link rel="stylesheet" href="https://fonts.googleapis.com/css?family=Balthazar">
    <link rel="stylesheet" href="style.css">
    <script src="calc.js"></script>
  </head>

  <body>
    <div class="confirm">
      <h1>Wizard Sim Level Calculator</h1>
      <h3>Enter your desired level below</h3>
      <br>
      <div id="desired-level">
        <button onclick="this.parentNode.querySelector('input[type=number]').stepDown(); adjustManaWell()">-</button>
        <input id="level-input" min="0" max="150" name="quantity" value="1" type="number" onchange="adjustManaWell()">
        <button onclick="this.parentNode.querySelector('input[type=number]').stepUp(); adjustManaWell()" class="plus">+</button>
      </div>
      <br>
    </div>


    <div id="mana-well">MANA WELL</div>

  </body>

</html>