slucent. */
                background: #404040;
            }
        }

        /* Allow canvas to fill entire web page: */
        html,
        body {
            overflow: hidden;
            margin: 0 !important;
            padding: 0 !important;
            height: 100%;
            width: 100%;
        }

        /* Make canvas fill entire document: */
        canvas {
            margin-right: auto;
            margin-left: auto;
            display: block;
            position: absolute;
        