Index: wp-admin/includes/template.php
===================================================================
--- wp-admin/includes/template.php	(revision 24730)
+++ wp-admin/includes/template.php	(working copy)
@@ -1000,6 +1000,7 @@
 		<ul class="outer-border">
 	<?php
 	$i = 0;
+	$first_open = false;
 	do {
 		if ( ! isset( $wp_meta_boxes ) || ! isset( $wp_meta_boxes[$page] ) || ! isset( $wp_meta_boxes[$page][$context] ) )
 			break;
@@ -1011,8 +1012,14 @@
 						continue;
 					$i++;
 					$hidden_class = in_array( $box['id'], $hidden ) ? 'hide-if-js' : '';
+
+					$open_class = '';
+					if ( ! $first_open && empty( $hidden_class ) ) {
+						$first_open = true;
+						$open_class = 'open';
+					}
 					?>
-					<li class="control-section accordion-section <?php echo $hidden_class; ?> <?php echo esc_attr( $box['id'] ); ?>" id="<?php echo esc_attr( $box['id'] ); ?>">
+					<li class="control-section accordion-section <?php echo $hidden_class; ?> <?php echo $open_class; ?> <?php echo esc_attr( $box['id'] ); ?>" id="<?php echo esc_attr( $box['id'] ); ?>">
 						<h3 class="accordion-section-title hndle" tabindex="0" title="<?php echo esc_attr( $box['title'] ); ?>"><?php echo esc_html( $box['title'] ); ?></h3>
 						<div class="accordion-section-content <?php postbox_classes( $box['id'], $page ); ?>">
 							<div class="inside">
Index: wp-admin/customize.php
===================================================================
--- wp-admin/customize.php	(revision 24730)
+++ wp-admin/customize.php	(working copy)
@@ -46,7 +46,7 @@
 wp_user_settings();
 _wp_admin_html_begin();
 
-$body_class = 'wp-core-ui';
+$body_class = 'wp-core-ui js';
 
 if ( wp_is_mobile() ) :
 	$body_class .= ' mobile';
@@ -90,8 +90,8 @@
 			$cannot_expand = ! ( $screenshot || $wp_customize->theme()->get('Description') );
 		?>
 
-		<div class="wp-full-overlay-sidebar-content" tabindex="-1">
-			<div id="customize-info" class="accordion-section<?php if ( $cannot_expand ) echo ' cannot-expand'; ?>">
+		<div class="wp-full-overlay-sidebar-content accordion-container" tabindex="-1">
+			<div id="customize-info" class="accordion-section <?php if ( $cannot_expand ) echo ' cannot-expand'; ?>">
 				<div class="accordion-section-title" aria-label="<?php esc_attr_e( 'Theme Customizer Options' ); ?>" tabindex="0">
 					<span class="preview-notice"><?php
 						/* translators: %s is the theme name in the Customize/Live Preview pane */
@@ -111,7 +111,7 @@
 				<?php endif; ?>
 			</div>
 
-			<div id="customize-theme-controls" class="accordion-container"><ul>
+			<div id="customize-theme-controls"><ul>
 				<?php
 				foreach ( $wp_customize->sections() as $section )
 					$section->maybe_render();
Index: wp-admin/js/accordion.js
===================================================================
--- wp-admin/js/accordion.js	(revision 24730)
+++ wp-admin/js/accordion.js	(working copy)
@@ -9,10 +9,9 @@
 			e.preventDefault(); // Keep this AFTER the key filter above
 
 			accordionSwitch( $( this ) );
-			accordionCorners();
 		});
 
-		// Refresh selected accordion option when screen options are toggled
+		// Re-initialize accordion when screen options are toggled
 		$( '.hide-postbox-tog' ).click( function () {
 			accordionInit();
 		});
@@ -22,33 +21,35 @@
 	var accordionOptions = $( '.accordion-container li.accordion-section' ),
 		sectionContent   = $( '.accordion-section-content' );
 
-	// Rounded corners
-	function accordionCorners () {
+	function accordionInit () {
+		// Rounded corners
 		accordionOptions.removeClass( 'top bottom' );
 		accordionOptions.filter( ':visible' ).first().addClass( 'top' );
-		accordionOptions.filter( ':visible' ).last().addClass( 'bottom' ).find( sectionContent ).addClass('bottom');
-	};
-
-	function accordionInit () {
-		accordionSwitch( accordionOptions.filter( ':visible' ).first() );
-		accordionCorners();
+		accordionOptions.filter( ':visible' ).last().addClass( 'bottom' ).find( sectionContent ).addClass( 'bottom' );
 	}
 
 	function accordionSwitch ( el ) {
 		var section = el.closest( '.accordion-section' ),
-		    siblings = section.parent().find( '.open' ),
-		    content = section.find( sectionContent );
+			siblings = section.closest( '.accordion-container' ).find( '.open' ),
+			content = section.find( sectionContent );
 
 		if ( section.hasClass( 'cannot-expand' ) )
 			return;
 
-		siblings.removeClass( 'open' );
-		siblings.find( sectionContent ).show().slideUp( 150 );
-		content.toggle( section.hasClass( 'open' ) ).slideToggle( 150 );
-		section.toggleClass( 'open' );
+		if ( section.hasClass( 'open' ) ) {
+			section.toggleClass( 'open' );
+			content.toggle( true ).slideToggle( 150 );
+		} else {
+			siblings.removeClass( 'open' );
+			siblings.find( sectionContent ).show().slideUp( 150 );
+			content.toggle( false ).slideToggle( 150 );
+			section.toggleClass( 'open' );
+		}
+
+		accordionInit();
 	}
 
-	// Show the first accordion option by default
+	// Initialize the accordion (currently just corner fixes)
 	accordionInit();
 
 })(jQuery);
Index: wp-admin/css/wp-admin.css
===================================================================
--- wp-admin/css/wp-admin.css	(revision 24730)
+++ wp-admin/css/wp-admin.css	(working copy)
@@ -9029,6 +9029,7 @@
 
 .control-section .accordion-section-title {
 	padding: 10px 20px;
+	color: #464646;
 	font-size: 15px;
 	font-family: Georgia, "Times New Roman", "Bitstream Charter", Times, serif;
 	font-weight: normal;
@@ -9045,34 +9046,21 @@
 	top: 15px;
 }
 
-.control-section .accordion-section-title:hover:after,
-.control-section .accordion-section-title:focus:after {
-	border-color: #eee transparent;
-}
-
 .js .control-section:hover .accordion-section-title,
 .js .control-section .accordion-section-title:hover,
 .js .control-section.open .accordion-section-title,
 .js .control-section .accordion-section-title:focus {
-	color: #fff;
-	text-shadow: 0 -1px 0 #333;
-	background: #808080;
-	background-image: -webkit-gradient(linear, left bottom, left top, from(#6d6d6d), to(#808080));
-	background-image: -webkit-linear-gradient(bottom, #6d6d6d, #808080);
-	background-image:    -moz-linear-gradient(bottom, #6d6d6d, #808080);
-	background-image:      -o-linear-gradient(bottom, #6d6d6d, #808080);
-	background-image: linear-gradient(to top, #6d6d6d, #808080);
-	border-left: 1px solid #808080;
-	border-right: 1px solid #808080;
+	color: #000;
+	background: #f9f9f9;
+	background-image: -webkit-gradient(linear, left bottom, left top, from(#ececec), to(#f9f9f9));
+	background-image: -webkit-linear-gradient(bottom, #ececec, #f9f9f9);
+	background-image:    -moz-linear-gradient(bottom, #ececec, #f9f9f9);
+	background-image:      -o-linear-gradient(bottom, #ececec, #f9f9f9);
+	background-image: linear-gradient(to top, #ececec, #f9f9f9);
 }
 
-.js .control-section.accordion-section:hover,
-.control-section.accordion-section.open {
-	border-top-color: #808080;
-}
-
 .control-section.open .accordion-section-title {
-	border-bottom: 1px solid #6d6d6d;
+	border-bottom: 1px solid #dfdfdf;
 }
 
 /* =Media Queries
Index: wp-admin/css/customize-controls.css
===================================================================
--- wp-admin/css/customize-controls.css	(revision 24730)
+++ wp-admin/css/customize-controls.css	(working copy)
@@ -121,6 +121,36 @@
 	height: 100%;
 }
 
+#customize-theme-controls .accordion-section-title:hover:after,
+#customize-theme-controls .accordion-section-title:focus:after {
+	border-color: #eee transparent;
+}
+
+#customize-theme-controls .control-section:hover .accordion-section-title,
+#customize-theme-controls .control-section .accordion-section-title:hover,
+#customize-theme-controls .control-section.open .accordion-section-title,
+#customize-theme-controls .control-section .accordion-section-title:focus {
+	color: #fff;
+	text-shadow: 0 -1px 0 #333;
+	background: #808080;
+	background-image: -webkit-gradient(linear, left bottom, left top, from(#6d6d6d), to(#808080));
+	background-image: -webkit-linear-gradient(bottom, #6d6d6d, #808080);
+	background-image:    -moz-linear-gradient(bottom, #6d6d6d, #808080);
+	background-image:      -o-linear-gradient(bottom, #6d6d6d, #808080);
+	background-image: linear-gradient(to top, #6d6d6d, #808080);
+	border-left: 1px solid #808080;
+	border-right: 1px solid #808080;
+}
+
+#customize-theme-controls .control-section.accordion-section:hover,
+#customize-theme-controls .control-section.accordion-section.open {
+	border-top-color: #808080;
+}
+
+#customize-theme-controls .control-section.open .accordion-section-title {
+	border-bottom: 1px solid #6d6d6d;
+}
+
 /*
  * Style for custom settings
  */