body#gameBody{margin:0;padding:0;background-color:#000}canvas#gameCanvas{position:absolute;inset:0;margin:auto;border:2px solid white}button#gameStartButton{position:absolute;inset:0;margin:auto;width:100px;height:24px}.error-message{color:red;font-family:Arial,sans-serif;font-size:20px;position:absolute;top:50%;left:50%;transform:translate(-50%,-50%)}