index.html

<html lang="en">
  <head>
    <meta charset="UTF-8" />
    <meta name="viewport" content="width=device-width, initial-scale=1.0" />
    <meta http-equiv="X-UA-Compatible" content="ie=edge" />
    <title>Treevolution</title>
    <style>
      canvas {
        position: absolute;
        top: 0;
        left: 0;
        width: 100vw;
        height: 100vh;
      }
      #choose-overlay {
        display: none;
        position: absolute;
        text-align: center;
        width: 400px;
        height: 300px;
        left: calc(50% - 200px);
        top: 50px;
      }
    </style>
  </head>
  <body>
    <canvas></canvas>
    <div id="choose-overlay">
      <h2>Invest in</h2>
      <button id="splitting-button">Splitting</button>
      <button id="length-button">Length</button>
      <button id="thickness-button">Thickness</button>
      <!-- <button id="curvy-button">Curvyness</button> -->
      <button id="nothing-button">Nothing</button>
    </div>
    <script src="Vector2.js"></script>
    <script src="StateMachine.js"></script>
    <script src="Branch.js"></script>
    <script src="main.js"></script>
  </body>
</html>