Here's the HTML we're going to use in this example:
<!DOCTYPE html> <html> <head> <meta charset="utf-8"> <meta http-equiv="X-UA-Compatible" content="IE=edge"> <meta name="viewport" content="width=device-width, initial-scale=1"> <title>Mastering RWD with HTML5 & CSS3</title> <link rel="stylesheet" href="css/site-styles.css"> <!--[if lt IE 9]> <script src="//html5shiv.googlecode.com/svn/trunk/html5.js"> </script> <![endif]--> </head> <body> <h1>Basic Layout Using a Custom CSS Grid</h1> <main class="container-12 clear" role="main"> <header class="grid-12" role="banner">Header (.grid-12)</header> <nav class="grid-4" role="navigation">Nav (.grid-4)</nav> <section class="grid-8"> <div class="row"> <div class="grid...