What are the potential pitfalls of including PHP files for CSS styling in a web development project?

Including PHP files for CSS styling in a web development project can lead to slower loading times and potential conflicts with caching mechanisms. To avoid these pitfalls, it's recommended to use CSS files for styling instead of PHP files.

// Instead of including a PHP file for CSS styling, use a CSS file directly in your HTML document like this:
<link rel="stylesheet" type="text/css" href="styles.css">