body{font-family:Arial,sans-serif;line-height:1.6;margin:0;padding:0;background-color:#f4f4f4;color:#333}header{background:#333;color:#fff;padding:1rem 0;text-align:center}p{font-size:1.2rem;margin:1rem 0}ol,ul{margin:1rem 0;padding-left:2rem}li{margin:.5rem 0}a{color:#007bff;text-decoration:none}a:hover{text-decoration:underline}#app{margin:2rem;padding:1rem;background:#fff;border:1px solid #ddd;border-radius:5px;box-shadow:0 0 10px #0000001a}