body{font-family:Arial,sans-serif;background:#f9f9f9;margin:0;padding:20px}.container{max-width:900px;margin:0 auto}.box{border:1px solid #ddd;padding:10px;margin-bottom:15px}input{padding:6px;margin:3px}button{margin:3px;padding:6px 10px}.table{width:100%;border-collapse:collapse}.table th,.table td{border:1px solid #ddd;padding:6px;text-align:left}.error{color:red}