body{font-family:Arial,sans-serif;padding:20px;background:#f5f5f5}h1{color:#333}.container{background:#fff;padding:20px;border-radius:8px;max-width:600px}button,pre{padding:10px}input{display:block;margin:10px 0;padding:8px;width:100%}button{margin-top:10px;cursor:pointer}pre{background:#222;color:#0f0;overflow:auto}