Index: wp-content/themes/twentytwelve/header.php
===================================================================
--- wp-content/themes/twentytwelve/header.php	(revision 21435)
+++ wp-content/themes/twentytwelve/header.php	(working copy)
@@ -9,7 +9,15 @@
  * @since Twenty Twelve 1.0
  */
 ?><!DOCTYPE html>
+<!--[if IE 7]>
+<html id="ie7" <?php language_attributes(); ?>>
+<![endif]-->
+<!--[if IE 8]>
+<html id="ie8" <?php language_attributes(); ?>>
+<![endif]-->
+<!--[if !(IE 7) | !(IE 8)  ]><!-->
 <html <?php language_attributes(); ?>>
+<!--<![endif]-->
 <head>
 <meta charset="<?php bloginfo( 'charset' ); ?>" />
 <meta name="viewport" content="width=device-width, initial-scale=1.0" />
@@ -18,6 +26,7 @@
 <link rel="pingback" href="<?php bloginfo( 'pingback_url' ); ?>" />
 <!--[if lt IE 9]>
 <script src="<?php echo get_template_directory_uri(); ?>/js/html5.js" type="text/javascript"></script>
+<script src="<?php echo get_template_directory_uri(); ?>/js/css3-mediaqueries.js" type="text/javascript"></script>
 <![endif]-->
 <?php wp_head(); ?>
 </head>
