This is an example of using HTML5/CSS3 manipulated with the Modernizr Javascript Library using the Javascript (instead of CSS) method for differentiating the various browser implimentations of capabilities. This example uses the HTML5 Tags for header, content, section and footer. For the alternative to this method, you can Click Here to view the CSS coding style. Note how there is a break between the containers using the Javascript method, where there are none using the CSS method.
Also note that the jQuery library is also used to help with the DOM targeting, but is hosted on a remote site (google) with the header tags. For more on the how to use jQuery to do more on your webpage, I suggest This Tutorial for a better understanding.
Sure, just View Source with your browser right now, and you can view all the code necesary, including the CSS. The other files like jQuery and Modernizr don't need to be seen for you to get the full picture of how this is being accmplished.