Lesson Code: http://www.developphp.com/video/CSS/Media-Queries-Responsive-Website-Layout-Tutorial
Learn to create responsive website layouts using CSS3 media queries. Media queries allow us to target a particular media type and then apply zero or more expressions that check for the conditions of particular media features. Using this logic we can adjust all CSS for our site according to the screen size of the device that a user is viewing it with. It will also be responsive if the user resizes their browser window well after your page loads. An alternative to a responsive layout is to simply use percentages for the width values of your elements. But some developers must completely restructure the layout according to the screen size of the viewer. That is where a responsive layout is applied. It also makes you look very capable in your web site design skills.