Media queries allow you to style elements for specific devices (smartphones, tablets, desktop computers) by using attributes like width, height, resolution, aspect ratio, orientation or color. By using media queries, presentations can be tailored to a specific range of output devices without changing the content itself.
Example:

<link rel="stylesheet" media="screen and (min-width: 480px) and (max-width: 960px)" 
href="480-960.css" />
 
<!-- OR -->
@media screen and (min-width: 480px) and (max-width: 960px) {
    #header {
        display: none;
    }
}

An @media rule specifies the target media types of a set of statements. In the example above, we are specifying the media type screen. The max-width and min-width features are telling the browser that at any screen size larger than 480px, but smaller than 960px, hide any elements with id="header".