html, body {
    width: 100%;
    height: 100%;
    margin: 0;
    padding: 0;
    overflow: hidden;
    background: black;
}

.hidden {
	display: none;
}

#game {
	position: absolute;
    top: 0;
    right: 0;
    bottom: 0;
    left: 0;
    margin: auto;
}