In Video 03f, David Cochran completes his basic grid system by providing a single transition using a media query. At widths smaller than 768px wide, our design will have a single column, so that the content can easily flow vertically down a narrow screen. But once we have a screen size that is at least 768px wide, the three-column layout will kick in, allowing us to make efficient use of the available screen space.

Course Example 03-10 contains the code demonstrated in this video.