How can PHP developers ensure that included external content is responsive and compatible with different devices?

To ensure that included external content is responsive and compatible with different devices, PHP developers can use CSS media queries to adjust the styling based on the device's screen size. By setting specific styles for different screen sizes, the content can adapt and display properly on various devices.

<?php
echo '<style>
@media screen and (max-width: 600px) {
   /* Add responsive styles here */
}
</style>';
?>