body{display:flex;justify-content:center;align-items:center;height:100vh;margin:0;font-family:sans-serif;background:#f5f5f5}.box{background:#fff;padding:40px;border-radius:8px;text-align:center;box-shadow:0 2px 10px rgba(0,0,0,.1)}input{padding:10px;border:1px solid #ccc;border-radius:4px;font-size:16px}button{margin-top:15px;padding:10px 25px;background:#0073aa;color:#fff;border:none;border-radius:4px;cursor:pointer;font-size:16px}.error{color:red;margin-top:10px}