David Powers is an author and trainer. He's written more than a dozen books on web development, focusing mainly on PHP, Dreamweaver, and CSS.
Talks I've Given
Mastering Media Queries
Featuring David Powers
CSS3 media queries allow you to deliver different styles to the browser depending on features such as the width and orientation of the device on which a website is being viewed. David Powers explains what media queries are, how to use them, and how to avoid some of the main pitfalls.css3 media-queries html5