Index: wp-content/themes/twentytwelve/style.css
===================================================================
--- wp-content/themes/twentytwelve/style.css	(revision 21522)
+++ wp-content/themes/twentytwelve/style.css	(working copy)
@@ -508,7 +508,6 @@
 
 /* Navigation Menu */
 .main-navigation .menu {
-	display: inline-block;
 	margin-top: 24px;
 	margin-top: 1.714285714rem;
 	width: 100%;
@@ -588,31 +587,6 @@
 	color: #636363;
 	font-weight: bold;
 }
-nav[role="navigation"].main-small-navigation {
-	margin-top: 24px;
-	margin-top: 1.714285714rem;
-	text-align: center;
-}
-nav[role="navigation"].main-small-navigation li {
-	margin-top: 24px;
-	margin-top: 1.714285714rem;
-	font-size: 12px;
-	font-size: 0.857142857rem;
-	line-height: 2;
-	float: none;
-}
-nav[role="navigation"].main-small-navigation a {
-	color: #5e5e5e;
-}
-nav[role="navigation"].main-small-navigation a:hover {
-	color: #21759b;
-}
-.menu-toggle {
-	display: inline-block;
-}
-.main-small-navigation .menu {
-	display: none;
-}
 
 /* Banner */
 section[role="banner"] {
@@ -1368,6 +1342,39 @@
 /* =Media queries
 -------------------------------------------------------------- */
 
+/* Maximum width of 599 pixels. */
+@media screen and (max-width: 599px) {
+	nav[role="navigation"].main-navigation {
+		margin-top: 24px;
+		margin-top: 1.714285714rem;
+		text-align: center;
+	}
+	nav[role="navigation"].main-navigation li {
+		margin-right: 0;
+		margin-top: 24px;
+		margin-top: 1.714285714rem;
+		font-size: 12px;
+		font-size: 0.857142857rem;
+		line-height: 2;
+		float: none;
+	}
+	nav[role="navigation"].main-navigation a {
+		color: #5e5e5e;
+	}
+	nav[role="navigation"].main-navigation a:hover {
+		color: #21759b;
+	}
+	.menu-toggle {
+		clip: auto;
+		display: inline-block;
+		position: relative !important;
+	}
+	.main-navigation .menu {
+		border: 0;
+		display: none;
+	}
+}
+
 /* Minimum width of 600 pixels. */
 @media screen and (min-width: 600px) {
 	.entry-content p,
@@ -1447,6 +1454,9 @@
 		margin: 0 0 24px;
 		margin: 0 0 1.714285714rem;
 	}
+	.main-navigation .menu {
+		display: inline-block !important;
+	}
 }
 
 /* Minimum width of 960 pixels. */
Index: wp-content/themes/twentytwelve/header.php
===================================================================
--- wp-content/themes/twentytwelve/header.php	(revision 21522)
+++ wp-content/themes/twentytwelve/header.php	(working copy)
@@ -36,7 +36,7 @@
 		</hgroup>
 
 		<nav class="site-navigation main-navigation" role="navigation">
-			<h3 class="assistive-text"><?php _e( 'Show navigation', 'twentytwelve' ); ?></h3>
+			<h3 class="assistive-text menu-toggle"><?php _e( 'Show navigation', 'twentytwelve' ); ?></h3>
 			<div class="skip-link assistive-text"><a href="#content" title="<?php esc_attr_e( 'Skip to content', 'twentytwelve' ); ?>"><?php _e( 'Skip to content', 'twentytwelve' ); ?></a></div>
 			<?php wp_nav_menu( array( 'theme_location' => 'primary' ) ); ?>
 		</nav>
Index: wp-content/themes/twentytwelve/js/theme.js
===================================================================
--- wp-content/themes/twentytwelve/js/theme.js	(revision 21522)
+++ wp-content/themes/twentytwelve/js/theme.js	(working copy)
@@ -5,42 +5,15 @@
  */
 
 jQuery( document ).ready( function( $ ) {
-	var masthead = $( '#masthead' ),
-		largeWindow = window.matchMedia( 'screen and (min-width: 600px)' ),
-		timeout = false;
-
-	$.fn.smallMenu = function() {
-		if ( ! masthead.find( '.menu' ).children().length ) {
-			$( '.menu-toggle' ).remove();
-			return;
-		}
+	
+	if ( ! $( '#masthead .menu' ).children().length ) {
+		$( '.menu-toggle' ).remove();
+		return;
+	}
 
-		masthead.find( '.site-navigation' ).removeClass( 'main-navigation' ).addClass( 'main-small-navigation' );
-		masthead.find( '.site-navigation h3' ).removeClass( 'assistive-text' ).addClass( 'menu-toggle' );
-
-		$( '.menu-toggle' ).off( 'click' ).click( function() {
-			masthead.find( '.menu' ).stop().slideToggle();
-			$( this ).toggleClass( 'toggled-on' );
-		} );
-	};
-
-	// Check viewport width on first load.
-	if ( ! largeWindow.matches )
-		$.fn.smallMenu();
-
-	// Check viewport width when user resizes the browser window.
-	$( window ).resize( function() {
-		if ( false !== timeout )
-			clearTimeout( timeout );
-
-		timeout = setTimeout( function() {
-			if ( ! largeWindow.matches ) {
-				$.fn.smallMenu();
-			} else {
-				masthead.find( '.site-navigation' ).removeClass( 'main-small-navigation' ).addClass( 'main-navigation' );
-				masthead.find( '.site-navigation h3' ).removeClass( 'menu-toggle' ).addClass( 'assistive-text' );
-				masthead.find( '.menu' ).removeAttr( 'style' );
-			}
-		}, 200 );
+	$( '.menu-toggle' ).off( 'click' ).click( function() {
+		$( '#masthead .menu' ).stop().slideToggle();
+		$( this ).toggleClass( 'toggled-on' );
 	} );
+	
 } );
\ No newline at end of file