*{box-sizing:border-box;margin:0;padding:0}body{color:#000;background:#fff;font-family:Arial,sans-serif}.app{text-align:center;border:1px solid #ddd;border-radius:8px;max-width:400px;margin:80px auto;padding:25px}input{border:1px solid #ccc;border-radius:5px;width:90%;margin:8px 0;padding:8px}button{color:#fff;cursor:pointer;background:#007bff;border:none;border-radius:5px;margin:5px;padding:8px 12px}button:hover{background:#0056b3}h2{margin-bottom:15px}p{margin:10px 0}