What purpose do media queries serve in CSS?

Media queries serve a crucial role in ensuring that styles are applied appropriately based on the characteristics of the device being used to view a webpage. They allow web developers to create responsive designs that adapt to different screen sizes, orientations, and resolutions. By using media queries, specific CSS rules can be tailored for various device attributes, such as width and height, allowing for a flexible layout that enhances user experience across a range of devices, from mobile phones to desktop computers.

This approach helps maintain usability and readability of the content, ensuring that it renders well regardless of how the visitor accesses the website. For instance, you might use a media query to apply specific styles that only activate when the browser window is narrower than a certain width, which is particularly useful for optimizing layouts for mobile devices.

While other options like improving loading speed, validating user input, or creating animations might be relevant tasks in web development, they do not relate to the specific functionality of media queries. Media queries are unique in their ability to adapt and modify CSS based on real-time conditions of the viewing environment.