body{background-color:#000;margin:0;padding:0}#mainDisplay{background-color:#000;width:max(320px,min(512px,min(100vw,100vh)));height:max(320px,min(512px,min(100vw,100vh)));margin:max(0px,50vh - max(320px,min(512px,min(100vw,100vh)))/2) auto 0;padding:0;display:block}