JSRay/src/styles.css

* { margin: 0; padding: 0; outline: 0; }

html, body {
	height: 100%;
}

body {
	background-color: #444;
}

.container {
	display: flex;
	align-items: center;
	justify-content: center;
	height: 100%;
}

canvas {
	border: 2px solid #000;
}