React Js Calculate Area & Perimeter of Circle

<!DOCTYPE html>
<html>

<body>
  <div id="app"></div>
  <script type="text/babel">
    const { useState } = React;
    function App() {
      const [inputValue, setInputValue] = useState('');
      const [result, setResult] = useState('');

return (
       <div className='container'>
          <h1 className='title'>React Js Circle Area Calculator</h1>
          <label className='label'>
            Enter the radius of the circle:
            <input
              type="number"
              value={inputValue}
              onChange={(e) => setInputValue(e.target.value)}
              className='input'
            />
          </label>
          <button onClick={calculateArea} className='button'>Calculate</button>
          <div className='result'>
            {result && <p className='result-text'>{result}</p>}
          </div>
        </div>

);
    }

ReactDOM.render(<App />, document.getElementById("app"));
  </script>
  <style>
    .container {
      font-family: Arial, sans-serif;
      padding: 20px;
      border-radius: 5px;
      box-shadow: 0px 0px 10px rgba(0, 0, 0, 0.2);
      max-width: 600px;
      margin: 0 auto;
      text-align: center;
    }

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

.label {
  font-size: 18px;
  display: block;
  margin-bottom: 10px;
  color: #555;
}

.input {
  width: 100%;
  padding: 10px;
  font-size: 16px;
  border: 1px solid #ccc;
  border-radius: 5px;
  margin-bottom: 20px;
  box-sizing: border-box;
}

.button {
  background-color: #007bff;
  color: #fff;
  font-size: 16px;
  padding: 10px 20px;
  border: none;
  border-radius: 5px;
  cursor: pointer;
  transition: background-color 0.3s ease;
}

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

.result {
  margin-top: 20px;
}

.result-text {
  font-size: 18px;
  color: #333;
  background-color: #fff;
  padding: 10px;
  border: 1px solid #ccc;
  border-radius: 5px;
  
}
  </style>

</body>

</html>