canvas {
    position: absolute;
    left: 50%;
    top: 50%;
    transform: translate(-50%, -50%);
    width: 50%;
    height: 50%;
    padding: 20px;
    text-align: center;
    margin: 0;  
   
  }

  .vid{display: block;
    margin-left: auto; 
    margin-right: auto;width:80%;height:auto;
    overflow: -moz-hidden-unscrollable;}

    html, body {
      width:  100%;
      height: 100%;
      margin: 0;
      display: block;
      overflow: hidden;
    }