How can issues with loading CSS and JavaScript files be resolved when using custom PHP URL routing?

When using custom PHP URL routing, issues with loading CSS and JavaScript files can be resolved by using absolute paths for these resources in your HTML templates. This ensures that the browser can locate and load the files correctly regardless of the current URL.

```php
<link rel="stylesheet" type="text/css" href="<?php echo BASE_URL; ?>/css/style.css">
<script src="<?php echo BASE_URL; ?>/js/script.js"></script>
```

In the above code snippet, `BASE_URL` should be defined as the root URL of your website in a configuration file or at the beginning of your PHP script. This way, the CSS and JavaScript files will be loaded correctly even when using custom PHP URL routing.