Add support for GetMonitorWidth/Height

[mundusnine]

the css needs to be changed to this to actually view the effect:

        body {
            /* Lite Mode */
            background: var(--color-lite);
            color: var(--color-dark);
            margin: 0px;
            border: 0;
           /*  Disable scrollbars */
            overflow: hidden;
            /* No floating content on sides */
            display: block;
            /* Dark Mode */
            @media (prefers-color-scheme: dark) {
                background: var(--color-dark);
                color: var(--color-lite);
            }
        }

        #game {
            position: absolute;
            top: 0px;
            left: 0px;
            /* transform: translate(-50%, -50%); */
            border: 1px solid var(--color-dark);

            @media (prefers-color-scheme: dark) {
               border: 1px solid var(--color-lite);
            }

        }