body{font-family:sans-serif;margin:20px;padding:0;display:flex;justify-content:center;align-items:center;min-height:100vh;background-color:#f0f0f0}h1{text-align:center;margin-bottom:20px}li{list-style:none;margin-bottom:5px}button{background-color:#fff;border:1px solid #999;padding:5px 10px;cursor:pointer;border-radius:5px}button:hover{background-color:#eee}