React Js Check First Letter of String is Uppercase

<!DOCTYPE html>
<html>

<body>
  <div id="app"></div>
   <script type="text/babel">
    const { useState } = React;
    function App() {
      const [inputText, setInputText] = useState('');
      const isUppercase = /^[A-Z]/.test(inputText);

return (
        <div className='container'>
          <input
            type="text"
            placeholder="Enter a string"
            onChange={(e) => setInputText(e.target.value)}
            className="input-element"
          />
          <p className="paragraph-element">Is the first letter uppercase? {isUppercase ? 'Yes' : 'No'}</p>
        </div>

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

.input-element {
      padding: 10px;
      border: 2px solid #ccc;
      border-radius: 5px;
      width: 300px;
      font-size: 16px;
      margin-bottom: 20px;
      text-align: center;
    }

.input-element::placeholder {
      color: #aaa;
    }

.paragraph-element {
      font-size: 20px;
      color: #333;
      text-align: center;
    }

/* Style for the "Yes" and "No" text */
    .paragraph-element::before {
      content: 'Is the first letter uppercase? ';
      font-weight: bold;
    }

.paragraph-element::after {
      content: '';
      display: inline-block;
      width: 10px;
      height: 10px;
      border-radius: 50%;
      margin-left: 5px;
    }

/* Styling for the "Yes" and "No" indicator */
    .paragraph-element::after {
      content: '';
      display: inline-block;
      width: 10px;
      height: 10px;
      border-radius: 50%;
      margin-left: 5px;
    }

.paragraph-element::after {
      content: '';
      display: inline-block;
      width: 10px;
      height: 10px;
      border-radius: 50%;
      margin-left: 5px;
    }

/* Styling for the "Yes" and "No" indicator based on the state */
    .paragraph-element::after {
      content: '';
      display: inline-block;
      width: 10px;
      height: 10px;
      border-radius: 50%;
      margin-left: 5px;
      background-color: #5ab45e;
      /* Green for "Yes" */
    }

.paragraph-element::before {
      content: 'Is the first letter uppercase? ';
      font-weight: bold;
    }

.paragraph-element::after {
      content: '';
      display: inline-block;
      width: 10px;
      height: 10px;
      border-radius: 50%;
      margin-left: 5px;
      background-color: #f44336;
      /* Red for "No" */
    }
  </style>
</body>

</html>

 
<!DOCTYPE html>
<html>
​
<head>
  <meta charset="UTF-8" />
  <script src="https://unpkg.com/react@17.0.2/umd/react.development.js"></script>
  <script src="https://unpkg.com/react-dom@17.0.2/umd/react-dom.development.js"></script>
  <script src="https://unpkg.com/@babel/standalone@7.14.7/babel.min.js"></script>
</head>
​
<body>
  <div id="app"></div>
   <script type="text/babel">
    const { useState } = React;
    function App() {
      const [inputText, setInputText] = useState('');
      const isUppercase = /^[A-Z]/.test(inputText);
​
      return (
        <div className='container'>
          <input
            type="text"
            placeholder="Enter a string"
            onChange={(e) => setInputText(e.target.value)}
            className="input-element"
          />
          <p className="paragraph-element">Is the first letter uppercase? {isUppercase ? 'Yes' : 'No'}</p>
        </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;
    }
​
​
    .input-element {
      padding: 10px;
      border: 2px solid #ccc;
      border-radius: 5px;
      width: 300px;
      font-size: 16px;
      margin-bottom: 20px;
      text-align: center;
    }
​
    .input-element::placeholder {
      color: #aaa;
    }
​
    .paragraph-element {
      font-size: 20px;
      color: #333;
      text-align: center;
    }
​
    /* Style for the "Yes" and "No" text */
    .paragraph-element::before {
      content: 'Is the first letter uppercase? ';
      font-weight: bold;
    }
​
    .paragraph-element::after {
      content: '';
      display: inline-block;
      width: 10px;
      height: 10px;
      border-radius: 50%;
      margin-left: 5px;
    }
​
    /* Styling for the "Yes" and "No" indicator */
    .paragraph-element::after {
      content: '';
      display: inline-block;
      width: 10px;
      height: 10px;
      border-radius: 50%;
      margin-left: 5px;
    }
​
    .paragraph-element::after {
      content: '';
      display: inline-block;
      width: 10px;
      height: 10px;
      border-radius: 50%;
      margin-left: 5px;
    }
​
    /* Styling for the "Yes" and "No" indicator based on the state */
    .paragraph-element::after {
      content: '';
      display: inline-block;
      width: 10px;
      height: 10px;
      border-radius: 50%;
      margin-left: 5px;
      background-color: #5ab45e;
      /* Green for "Yes" */
    }
​
    .paragraph-element::before {
      content: 'Is the first letter uppercase? ';
      font-weight: bold;
    }
​
    .paragraph-element::after {
      content: '';
      display: inline-block;
      width: 10px;
      height: 10px;
      border-radius: 50%;
      margin-left: 5px;
      background-color: #f44336;
      /* Red for "No" */
    }
  </style>
</body>
​
</html>