html,
body {
    margin: 0px;
    padding: 0px;
    border: 0px;
}

/*#CSCanvas { width: 100%;
   padding-bottom: 56.25%;
  
   }
*/

#CSCanvas {
    width: 100vw;
    height: 56.25vw; /* height:width ratio = 9/16 = .5625  */
    max-height: 100vh;
    max-width: 177.78vh; /* 16/9 = 1.778 */
    margin: auto;
    position: absolute;
    top: 0;
    bottom: 0; /* vertical center */
    left: 0;
    right: 0; /* horizontal center */
}