What are the potential pitfalls of using inline CSS styles in PHP code for layout purposes?

Using inline CSS styles in PHP code for layout purposes can lead to a lack of separation of concerns, making it harder to maintain and update the code. It can also make the code less reusable and harder to debug. A better approach would be to separate the CSS styles into a separate stylesheet and link it to the PHP file.

<!DOCTYPE html>
<html>
<head>
    <link rel="stylesheet" type="text/css" href="styles.css">
</head>
<body>
    <div class="container">
        <p>This is some content.</p>
    </div>
</body>
</html>