gistfile1.diff

Index: wp-content/themes/twentytwelve/style.css
===================================================================
--- wp-content/themes/twentytwelve/style.css	(revision 21639)
+++ wp-content/themes/twentytwelve/style.css	(working copy)
@@ -437,10 +437,13 @@
 body {
 	font-size: 14px;
 	font-size: 1rem;
-	font-family: "Open Sans", Helvetica, Arial, sans-serif;
+	font-family: Helvetica, Arial, sans-serif;
 	text-rendering: optimizeLegibility;
 	color: #444;
 }
+body.open-sans {
+	font-family: "Open Sans", Helvetica, Arial, sans-serif;
+}
 a {
 	outline: none;
 	color: #21759b;
Index: wp-content/themes/twentytwelve/functions.php
===================================================================
--- wp-content/themes/twentytwelve/functions.php	(revision 21639)
+++ wp-content/themes/twentytwelve/functions.php	(working copy)
@@ -373,6 +373,9 @@
 	elseif ( in_array( $background_color, array( 'fff', 'ffffff' ) ) )
 		$classes[] = 'custom-background-white';
 
+	if ( wp_script_is( 'twentytwelve-fonts', 'queue' ) )
+		$classes[] = 'open-sans';
+
 	return $classes;
 }
 add_filter( 'body_class', 'twentytwelve_body_class' );