canvas {
 	padding: 0px;
 	margin-top: 0px;
 	margin-right: 0px;
 	margin-bottom: 0px;
 	margin-left: 0px;
 	position: absolute;
 	top: 0;
 	left: 0;
 	width: 800px;
 	height: 450px;
}



.overlay{
 	padding: 0px;
 	margin-top: 0px;
 	margin-right: 0px;
 	margin-bottom: 0px;
 	margin-left: 0px;
 	position: absolute;
 	top: 0;
 	left: 0;
 	opacity: 0.0;
}

.back{
	background-image: url("../images/test_chamber.png");
	background-repeat: repeat;
	background-size: 800px, 450px;
	width: 800px;
 	height: 450px;
}

.overlayHB{
 	padding: 0px;
 	margin-top: 0px;
 	margin-right: 0px;
 	margin-bottom: 0px;
 	margin-left: 0px;
 	position: absolute;
 	top: 0;
 	left: -1000;
 	opacity: 1.0;
}