html,body{background:#000;width:100%;height:100%;margin:0;padding:0;overflow:hidden}canvas{display:block}#fullscreenBtn{z-index:10;letter-spacing:.5px;color:#ffffff26;cursor:pointer;background:#ffffff0f;border:none;border-radius:6px;padding:6px 12px;font-size:12px;transition:background .2s,color .2s;position:absolute;top:12px;left:12px}#fullscreenBtn:hover{color:#ffffffd9;background:#ffffff26}