Index: wp-content/themes/twentytwelve/header.php
===================================================================
--- wp-content/themes/twentytwelve/header.php	(revision 21443)
+++ wp-content/themes/twentytwelve/header.php	(working copy)
@@ -9,7 +9,18 @@
  * @since Twenty Twelve 1.0
  */
 ?><!DOCTYPE html>
+<!--[if IE 6]>
+<html class="ie6" <?php language_attributes(); ?>>
+<![endif]-->
+<!--[if IE 7]>
+<html class="ie7" <?php language_attributes(); ?>>
+<![endif]-->
+<!--[if IE 8]>
+<html class="ie8" <?php language_attributes(); ?>>
+<![endif]-->
+<!--[if !(IE 6) | !(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" />
Index: wp-content/themes/twentytwelve/style.css
===================================================================
--- wp-content/themes/twentytwelve/style.css	(revision 21443)
+++ wp-content/themes/twentytwelve/style.css	(working copy)
@@ -1546,4 +1546,27 @@
 		margin-left: 50px;
 		margin-left: 3.57142857rem;
 	}
+}
+
+
+/* =IE7 & IE8
+----------------------------------------------- */
+
+body {
+	background-color: #e6e6e6;
+}
+.ie7 .site,
+.ie8 .site {
+	max-width: 960px;
+	margin: 3.42857em auto;
+}
+.ie7 .site-content,
+.ie8 .site-content {
+	float: left;
+	width: 65.1042%;
+}
+.ie7 .widget-area,
+.ie8 .widget-area {
+	float: right;
+	width: 26.0417%;
 }
\ No newline at end of file
