html,body{background:#000;color:#fff}body{display:flex;justify-content:center;align-items:center}.paddle{background:#fff;height:20px;width:150px;position:absolute;bottom:10px;transition:all .15s linear}.ball{background:#fff;height:25px;width:25px;border-radius:99px;position:absolute;transition:left,right .15s linear}.game-container{border:1px solid #efefef;position:relative}.start-page{color:#fff;display:flex;justify-content:center;align-items:center}.start-page .header{font-size:50px}