body, html, #app {
    margin: 0;
    width: 100%;
    height: 100%;
    background-image: url("https://images.pexels.com/photos/2961995/pexels-photo-2961995.jpeg?auto=compress&cs=tinysrgb&h=800&dpr=1");
  }
  
  #app {
    overflow: hidden;
    touch-action: pan-up;
    color: #ffffff;
    font-family: 'Montserrat', sans-serif;
    text-align: center;
    text-shadow: 0 0 5px #000000, 0 0 20px #000;
    user-select: none;
  }
  
  #app h1 {
    --fontSize: 50px;
    --lineHeight: 70px;
    width: auto;
    height: calc(2 * var(--lineHeight));
    line-height: var(--lineHeight);
    margin: calc(50vh - var(--lineHeight)) auto 0;
    font-size: var(--fontSize);
      
  }
  
  #app a {
    margin-top: 10px;
    display: inline-block;
    text-decoration: none;
    color: #fff;
  }
  
  #app canvas {
    display: block;
    position: fixed;
    z-index: -1;
    top: 0;
  }
  
  @keyframes flap {
      0%, 20%, 80%, 100% {
          transform: scaleX(1) rotate(5deg);
      }
      50% {
          transform: scaleX(0.7) rotate(7deg);
      }
  }
  
  h1 {
      text-align: center;
      font-size: 2rem;
  }
  
  h1 span {
      display: inline-block;
      animation: flap 0.75s infinite ease-in-out;
  }
  
  #controls {
      position: fixed;
      top: 10px;
      left: 10px;
      z-index: 100;
      display: flex;
      align-items: center;
  }
  .btn {
      background-color: rgba(0, 0, 0, 0.4);
      border: none;
      color: rgba(255, 255, 255, 0.4);
      padding: 10px;
      text-align: center;
      text-decoration: none;
      display: inline-block;
      font-size: 16px;
      margin: 2px 2px;
      cursor: pointer;
      border-radius: 5px;
      transition: background-color 0.3s;
  }
  .btn:hover {
      background-color: rgba(255, 255, 255, 0.2);
      color: rgba(255, 255, 0, 1);
  }
  #fullscreenBtn {
      font-size: 20px;
      z-index: 100;
  }