html,
  body {
    overflow: auto;
    width: 100%;
    margin: 0;
    padding: 0;
    text-align: center;
    background-color: pink;
  }
  
  h1{
    z-index: 1;
    color: darkred;
    text-align: center;
  }
  
  h2{
    z-index: 1;
    text-align: center;
  }

  #renderCanvas {
    width: 100%;
    height: 100%;
    touch-action: none;
  }
  
  #divCanvas {
    width: 100%;
    text-align: center;
    left:0;
  }

  /* Style the button that is used to open and close the collapsible content */
  .collapsible, .collapsibleUP {
      color: #222;
      cursor: pointer;
      width: 0px;
      border: none;
      outline: none;
      font-size: 15px;
  }

  /* Add a background color to the button if it is clicked on (add the .active class with JS), and when you move the mouse over it (hover) */
  .active, .collapsible:hover, .collapsibleUP:hover {
      color: #777;
  }

  /* Style the collapsible content. Note: hidden by default */
  .content {
      display: none;
      overflow: hidden;
  }