React Js Convert Positive Number to Negative

<!DOCTYPE html>
<html>

<body>
  <div id="app"></div>
  <script type="text/babel">
    const { useState } = React;
    function App() {
      const [inputNumber, setInputNumber] = useState('123');
      const [convertedNumber, setConvertedNumber] = useState('');

return (
        <div className='container'>
          <h3 className='title'>React Js Convert Positive to Negative Number</h3>
          <input
            type="text"
            className='input-field'
            placeholder="Enter a number"
            value={inputNumber}
            onChange={(e) => setInputNumber(e.target.value)}
          />
          <button className='convert-button' onClick={convertNumber}>Convert</button>
          <p className='converted-number'>{convertedNumber}</p>
        </div>

);
    }
    ReactDOM.render(<App />, document.getElementById("app"));
  </script>

.title {
      font-size: 24px;
      margin-bottom: 20px;
      color: #333;
    }

.input-field {
      width: 100%;
      padding: 10px;
      margin-bottom: 15px;
      border: 1px solid #ccc;
      border-radius: 5px;
      font-size: 16px;
      box-sizing: border-box;
    }

.convert-button {
      background-color: #007bff;
      color: #fff;
      border: none;
      border-radius: 5px;
      padding: 10px 20px;
      font-size: 18px;
      cursor: pointer;
      transition: background-color 0.3s ease;
    }

.convert-button:hover {
      background-color: #0056b3;
    }

.converted-number {
      font-size: 24px;
      font-weight: bold;
      color: #007bff;
      margin-top: 15px;
    }
  </style>
</body>

</html>