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 */
   }