How can utilizing separate CSS files instead of inline CSS improve the maintainability and scalability of a website?

Utilizing separate CSS files instead of inline CSS can improve the maintainability and scalability of a website by keeping all styling rules in one central location. This makes it easier to make global changes to the website's design without having to search through each individual HTML file. Additionally, separate CSS files allow for better organization and modularity, making it easier to manage and update styles as the website grows.

<!DOCTYPE html>
<html>
<head>
    <link rel="stylesheet" type="text/css" href="styles.css">
</head>
<body>
    <h1>This is a heading</h1>
    <p>This is a paragraph.</p>
</body>
</html>