html{
    width: 100%;
    overflow: hidden;
}
body {
    width:  100%;
    height: 100%;
    margin: 0;
    margin: 0;
    background-color: #9ac;
    transition: background-color 2s;
}
.visible{
    visibility: hidden;
    }
    .box:hover {
      opacity: 1;
      transition: opacity 0.5s, color 1s;
    }
    .box {
        z-index: 2;
      color: #eee;
      box-shadow: 0px 0px 20px 2px;
      opacity: 0.5;
      transition: opacity 0.5s, color 1s;
      border-color: #222;
      border-style: solid;
      border-width: 2px;
      position: fixed;
      right: 20px;
      top: 20px;
      width: 74px;
      background-color: #777;
      border-radius: 20px;
      margin-bottom: 5px;
      margin-top: 5px;
    }
    .btn {
        z-index: 3;
      width: 35px;
      height: 35px;
      border-radius: 50%;
      border-style: solid;
      border-color: #222;
      background-color: #ddd;
    }
    .textbox {
      opacity: 0.8;
      font-family: arial;
      margin: auto;
      margin-top: 80px;
      padding: 20px;
      background-color: #eee;
      transition: background-color 2s;
      color: #111;
      width: 400px;
      border-radius: 8px;
      box-shadow: 0px 0px 50px 0px;
    }
    canvas {
      position: fixed;
      left: 0px;
      top: 0px;
      z-index: -1;
    }