body {
/*    background-color: #000;*/
    margin: 0;
/*    overflow: hidden;*/
}

#drawing_canvas {
    position: absolute;
    margin: auto;
    width: 768px;
    height: 768px;
    top: 0;
    bottom: 0;
    left: 0;
    right: 0;
}

#start-screen {
    background-color: #000;
}