Index: wp-admin/admin-header.php
===================================================================
--- wp-admin/admin-header.php	(revision 22944)
+++ wp-admin/admin-header.php	(working copy)
@@ -97,7 +97,7 @@
 
 ?>
 </head>
-<body class="wp-admin no-js <?php echo apply_filters( 'admin_body_class', '' ) . " $admin_body_class"; ?>">
+<body class="wp-admin wp-core-ui no-js <?php echo apply_filters( 'admin_body_class', '' ) . " $admin_body_class"; ?>">
 <script type="text/javascript">
 	document.body.className = document.body.className.replace('no-js','js');
 </script>
Index: wp-admin/css/ie.css
===================================================================
--- wp-admin/css/ie.css	(revision 22944)
+++ wp-admin/css/ie.css	(working copy)
@@ -25,10 +25,6 @@
 	width: 35%;
 }
 
-.welcome-panel .welcome-button {
-	padding: 0 16px;
-}
- 
 #wp-fullscreen-title {
 	width: 97%;
 }
Index: wp-admin/css/wp-admin.css
===================================================================
--- wp-admin/css/wp-admin.css	(revision 22944)
+++ wp-admin/css/wp-admin.css	(working copy)
@@ -226,7 +226,11 @@
 .hidden,
 .js .closed .inside,
 .js .hide-if-js,
-.no-js .hide-if-no-js {
+.no-js .hide-if-no-js,
+.js.wp-core-ui .hide-if-js,
+.js .wp-core-ui .hide-if-js,
+.no-js.wp-core-ui .hide-if-no-js,
+.no-js .wp-core-ui .hide-if-no-js {
 	display: none;
 }
 
@@ -2293,12 +2297,8 @@
 	background-position: 100% 17%;
 }
 
-.welcome-panel .welcome-button {
-	font: normal 15px sans-serif;
-	height: 46px;
-	line-height: 44px;
+.wp-core-ui .welcome-panel .button.button-hero {
     margin: 15px 0 3px;
-    padding: 0 36px;
 }
 
 .welcome-panel-content {
@@ -2377,11 +2377,6 @@
 }
 
 @media screen and (max-width: 870px) {
-	.welcome-button {
-		font-size: 14px;
-		padding: 1em 2.3em;
-	}
-
 	.welcome-panel .welcome-panel-column,
 	.welcome-panel .welcome-panel-column:first-child {
 		display: block;
@@ -5683,7 +5678,11 @@
 ------------------------------------------------------------------------------*/
 
 .no-customize-support .hide-if-no-customize,
-.customize-support .hide-if-customize {
+.customize-support .hide-if-customize,
+.no-customize-support.wp-core-ui .hide-if-no-customize,
+.no-customize-support .wp-core-ui .hide-if-no-customize,
+.customize-support.wp-core-ui .hide-if-customize,
+.customize-support .wp-core-ui .hide-if-customize {
 	display: none;
 }
 
Index: wp-admin/customize.php
===================================================================
--- wp-admin/customize.php	(revision 22944)
+++ wp-admin/customize.php	(working copy)
@@ -44,7 +44,7 @@
 wp_user_settings();
 _wp_admin_html_begin();
 
-$body_class = '';
+$body_class = 'wp-core-ui';
 
 if ( wp_is_mobile() ) :
 	$body_class .= ' mobile';
Index: wp-admin/includes/dashboard.php
===================================================================
--- wp-admin/includes/dashboard.php	(revision 22944)
+++ wp-admin/includes/dashboard.php	(working copy)
@@ -1244,8 +1244,8 @@
 	<div class="welcome-panel-column-container">
 	<div class="welcome-panel-column">
 		<h4><?php _e( 'Get Started' ); ?></h4>
-		<a class="button-primary welcome-button load-customize hide-if-no-customize" href="<?php echo wp_customize_url(); ?>"><?php _e( 'Customize Your Site' ); ?></a>
-		<a class="button-primary welcome-button hide-if-customize" href="<?php echo admin_url( 'themes.php' ); ?>"><?php _e( 'Customize Your Site' ); ?></a>
+		<a class="button button-primary button-hero load-customize hide-if-no-customize" href="<?php echo wp_customize_url(); ?>"><?php _e( 'Customize Your Site' ); ?></a>
+		<a class="button button-primary button-hero hide-if-customize" href="<?php echo admin_url( 'themes.php' ); ?>"><?php _e( 'Customize Your Site' ); ?></a>
 		<?php if ( current_user_can( 'install_themes' ) || ( current_user_can( 'switch_themes' ) && count( wp_get_themes( array( 'allowed' => true ) ) ) > 1 ) ) : ?>
 			<p class="hide-if-no-customize"><?php printf( __( 'or, <a href="%s">change your theme completely</a>' ), admin_url( 'themes.php' ) ); ?></p>
 		<?php endif; ?>
Index: wp-admin/includes/media.php
===================================================================
--- wp-admin/includes/media.php	(revision 22944)
+++ wp-admin/includes/media.php	(working copy)
@@ -358,7 +358,7 @@
 	do_action( "admin_head_{$content_func}" );
 ?>
 </head>
-<body<?php if ( isset($GLOBALS['body_id']) ) echo ' id="' . $GLOBALS['body_id'] . '"'; ?> class="no-js">
+<body<?php if ( isset($GLOBALS['body_id']) ) echo ' id="' . $GLOBALS['body_id'] . '"'; ?> class="wp-core-ui no-js">
 <script type="text/javascript">
 document.body.className = document.body.className.replace('no-js', 'js');
 </script>
Index: wp-admin/includes/template.php
===================================================================
--- wp-admin/includes/template.php	(revision 22944)
+++ wp-admin/includes/template.php	(working copy)
@@ -1389,7 +1389,7 @@
 $admin_body_class .= ' locale-' . sanitize_html_class( strtolower( str_replace( '_', '-', get_locale() ) ) );
 ?>
 </head>
-<body<?php if ( isset($GLOBALS['body_id']) ) echo ' id="' . $GLOBALS['body_id'] . '"'; ?> class="wp-admin no-js iframe <?php echo apply_filters( 'admin_body_class', '' ) . ' ' . $admin_body_class; ?>">
+<body<?php if ( isset($GLOBALS['body_id']) ) echo ' id="' . $GLOBALS['body_id'] . '"'; ?> class="wp-admin wp-core-ui no-js iframe <?php echo apply_filters( 'admin_body_class', '' ) . ' ' . $admin_body_class; ?>">
 <script type="text/javascript">
 //<![CDATA[
 (function(){
Index: wp-admin/install.php
===================================================================
--- wp-admin/install.php	(revision 22944)
+++ wp-admin/install.php	(working copy)
@@ -15,7 +15,7 @@
 	<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
 	<title>Error: PHP is not running</title>
 </head>
-<body>
+<body class="wp-core-ui">
 	<h1 id="logo"><a href="http://wordpress.org/">WordPress</a></h1>
 	<h2>Error: PHP is not running</h2>
 	<p>WordPress requires that your web server is running PHP. Your server does not have PHP installed, or PHP is turned off.</p>
@@ -62,7 +62,7 @@
 	wp_admin_css( 'install', true );
 	?>
 </head>
-<body<?php if ( is_rtl() ) echo ' class="rtl"'; ?>>
+<body class="wp-core-ui<?php if ( is_rtl() ) echo ' rtl'; ?>">
 <h1 id="logo"><a href="<?php esc_attr_e( 'http://wordpress.org/' ); ?>"><?php _e( 'WordPress' ); ?></a></h1>
 
 <?php
Index: wp-admin/maint/repair.php
===================================================================
--- wp-admin/maint/repair.php	(revision 22944)
+++ wp-admin/maint/repair.php	(working copy)
@@ -16,11 +16,11 @@
 <head>
 	<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
 	<title><?php _e( 'WordPress &rsaquo; Database Repair' ); ?></title>
-	<?php 
+	<?php
 	wp_admin_css( 'install', true );
 	?>
 </head>
-<body>
+<body class="wp-core-ui">
 <h1 id="logo"><a href="<?php esc_attr_e( 'http://wordpress.org/' ); ?>"><?php _e( 'WordPress' ); ?></a></h1>
 
 <?php
Index: wp-admin/network/sites.php
===================================================================
--- wp-admin/network/sites.php	(revision 22944)
+++ wp-admin/network/sites.php	(working copy)
@@ -53,7 +53,7 @@
 
 	if ( 'confirm' === $_GET['action'] ) {
 		check_admin_referer( 'confirm' );
-		
+
 		if ( ! headers_sent() ) {
 			nocache_headers();
 			header( 'Content-Type: text/html; charset=utf-8' );
@@ -72,7 +72,7 @@
 				wp_admin_css( 'ie', true );
 				?>
 			</head>
-			<body>
+			<body class="wp-core-ui">
 				<h1 id="logo"><a href="<?php esc_attr_e( 'http://wordpress.org/' ); ?>"><?php _e( 'WordPress' ); ?></a></h1>
 				<form action="sites.php?action=<?php echo esc_attr( $_GET['action2'] ) ?>" method="post">
 					<input type="hidden" name="action" value="<?php echo esc_attr( $_GET['action2'] ) ?>" />
@@ -85,20 +85,20 @@
 			</body>
 		</html>
 		<?php
-		exit();	
+		exit();
 	}
-	
+
 	$updated_action = '';
-	
+
 	$manage_actions = array( 'deleteblog', 'allblogs', 'archiveblog', 'unarchiveblog', 'activateblog', 'deactivateblog', 'unspamblog', 'spamblog', 'unmatureblog', 'matureblog' );
-	if ( in_array( $_GET['action'], $manage_actions ) ) {		
+	if ( in_array( $_GET['action'], $manage_actions ) ) {
 		$action = $_GET['action'];
 		if ( 'allblogs' === $action )
 			$action = 'bulk-sites';
 
 		check_admin_referer( $action );
-	} 
-		
+	}
+
 	switch ( $_GET['action'] ) {
 
 		case 'deleteblog':
@@ -108,21 +108,21 @@
 			$updated_action = 'not_deleted';
 			if ( $id != '0' && $id != $current_site->blog_id && current_user_can( 'delete_site', $id ) ) {
 				wpmu_delete_blog( $id, true );
-				$updated_action = 'delete';	
+				$updated_action = 'delete';
 			}
 		break;
 
 		case 'allblogs':
 			if ( ( isset( $_POST['action'] ) || isset( $_POST['action2'] ) ) && isset( $_POST['allblogs'] ) ) {
 				$doaction = $_POST['action'] != -1 ? $_POST['action'] : $_POST['action2'];
-				
+
 				foreach ( (array) $_POST['allblogs'] as $key => $val ) {
 					if ( $val != '0' && $val != $current_site->blog_id ) {
 						switch ( $doaction ) {
 							case 'delete':
 								if ( ! current_user_can( 'delete_site', $val ) )
 									wp_die( __( 'You are not allowed to delete the site.' ) );
-								
+
 								$updated_action = 'all_delete';
 								wpmu_delete_blog( $val, true );
 							break;
@@ -162,16 +162,16 @@
 		case 'spamblog':
 			update_blog_status( $id, 'spam', ( 'spamblog' === $_GET['action'] ) ? '1' : '0' );
 		break;
-	
+
 		case 'unmatureblog':
 		case 'matureblog':
 			update_blog_status( $id, 'mature', ( 'matureblog' === $_GET['action'] ) ? '1' : '0' );
 		break;
 	}
-	
+
 	if ( empty( $updated_action ) && in_array( $_GET['action'], $manage_actions ) )
 		$updated_action = $_GET['action'];
-	
+
 	if ( ! empty( $updated_action ) ) {
 		wp_safe_redirect( add_query_arg( array( 'updated' => $updated_action ), wp_get_referer() ) );
 		exit();
@@ -218,7 +218,7 @@
 			$msg = apply_filters( 'network_sites_updated_message_' . $_GET['updated'], __( 'Settings saved.' ) );
 		break;
 	}
-	
+
 	if ( ! empty( $msg ) )
 		$msg = '<div class="updated" id="message"><p>' . $msg . '</p></div>';
 }
@@ -231,7 +231,7 @@
 <div class="wrap">
 <?php screen_icon( 'ms-admin' ); ?>
 <h2><?php _e( 'Sites' ) ?>
-	
+
 <?php if ( current_user_can( 'create_sites') ) : ?>
 	<a href="<?php echo network_admin_url('site-new.php'); ?>" class="add-new-h2"><?php echo esc_html_x( 'Add New', 'site' ); ?></a>
 <?php endif; ?>
@@ -241,8 +241,8 @@
 } ?>
 </h2>
 
-<?php echo $msg; ?>	
-	
+<?php echo $msg; ?>
+
 <form action="" method="get" id="ms-search">
 <?php $wp_list_table->search_box( __( 'Search Sites' ), 'site' ); ?>
 <input type="hidden" name="action" value="blogs" />
Index: wp-admin/press-this.php
===================================================================
--- wp-admin/press-this.php	(revision 22944)
+++ wp-admin/press-this.php	(working copy)
@@ -439,7 +439,7 @@
 $admin_body_class = ( is_rtl() ) ? 'rtl' : '';
 $admin_body_class .= ' locale-' . sanitize_html_class( strtolower( str_replace( '_', '-', get_locale() ) ) );
 ?>
-<body class="press-this wp-admin <?php echo $admin_body_class; ?>">
+<body class="press-this wp-admin wp-core-ui <?php echo $admin_body_class; ?>">
 <form action="press-this.php?action=post" method="post">
 <div id="poststuff" class="metabox-holder">
 	<div id="side-sortables" class="press-this-sidebar">
Index: wp-admin/setup-config.php
===================================================================
--- wp-admin/setup-config.php	(revision 22944)
+++ wp-admin/setup-config.php	(working copy)
@@ -99,7 +99,7 @@
 <link rel="stylesheet" href="../wp-includes/css/buttons.css?ver=<?php echo preg_replace( '/[^0-9a-z\.-]/i', '', $wp_version ); ?>" type="text/css" />
 
 </head>
-<body<?php if ( is_rtl() ) echo ' class="rtl"'; ?>>
+<body class="wp-core-ui<?php if ( is_rtl() ) echo ' rtl'; ?>">
 <h1 id="logo"><a href="<?php esc_attr_e( 'http://wordpress.org/' ); ?>"><?php _e( 'WordPress' ); ?></a></h1>
 <?php
 } // end function setup_config_display_header();
Index: wp-admin/upgrade.php
===================================================================
--- wp-admin/upgrade.php	(revision 22944)
+++ wp-admin/upgrade.php	(working copy)
@@ -57,7 +57,7 @@
 	wp_admin_css( 'ie', true );
 	?>
 </head>
-<body>
+<body class="wp-core-ui">
 <h1 id="logo"><a href="<?php esc_attr_e( 'http://wordpress.org/' ); ?>"><?php _e( 'WordPress' ); ?></a></h1>
 
 <?php if ( get_option( 'db_version' ) == $wp_db_version || !is_blog_installed() ) : ?>
Index: wp-includes/class-wp-editor.php
===================================================================
--- wp-includes/class-wp-editor.php	(revision 22944)
+++ wp-includes/class-wp-editor.php	(working copy)
@@ -113,7 +113,7 @@
 			$buttons .= '<a id="' . $editor_id . '-tmce" class="wp-switch-editor switch-tmce" onclick="switchEditors.switchto(this);">' . __('Visual') . "</a>\n";
 		}
 
-		echo '<div id="wp-' . $editor_id . '-wrap" class="wp-editor-wrap ' . $switch_class . '">';
+		echo '<div id="wp-' . $editor_id . '-wrap" class="wp-core-ui wp-editor-wrap ' . $switch_class . '">';
 
 		if ( self::$editor_buttons_css ) {
 			wp_print_styles('editor-buttons');
Index: wp-includes/css/admin-bar.css
===================================================================
--- wp-includes/css/admin-bar.css	(revision 22944)
+++ wp-includes/css/admin-bar.css	(working copy)
@@ -600,7 +600,11 @@
  * Customize support classes
  */
 .no-customize-support .hide-if-no-customize,
-.customize-support .hide-if-customize {
+.customize-support .hide-if-customize,
+.no-customize-support.wp-core-ui .hide-if-no-customize,
+.no-customize-support .wp-core-ui .hide-if-no-customize,
+.customize-support.wp-core-ui .hide-if-customize,
+.customize-support .wp-core-ui .hide-if-customize {
 	display: none;
 }
 
Index: wp-includes/css/buttons.css
===================================================================
--- wp-includes/css/buttons.css	(revision 22944)
+++ wp-includes/css/buttons.css	(working copy)
@@ -34,9 +34,9 @@
   1.0 - Button Layouts
 ---------------------------------------------------------------------------- */
 
-.button,
-.button-primary,
-.button-secondary {
+.wp-core-ui .button,
+.wp-core-ui .button-primary,
+.wp-core-ui .button-secondary {
 	display: inline-block;
 	text-decoration: none;
 	font-size: 12px;
@@ -57,43 +57,43 @@
 }
 
 /* Remove the dotted border on :focus and the extra padding in Firefox */
-button::-moz-focus-inner,
-input[type="reset"]::-moz-focus-inner,
-input[type="button"]::-moz-focus-inner,
-input[type="submit"]::-moz-focus-inner {
+.wp-core-ui button::-moz-focus-inner,
+.wp-core-ui input[type="reset"]::-moz-focus-inner,
+.wp-core-ui input[type="button"]::-moz-focus-inner,
+.wp-core-ui input[type="submit"]::-moz-focus-inner {
 	border-width: 1px 0;
 	border-style: solid none;
 	border-color: transparent;
 	padding: 0;
 }
 
-.button.button-large,
-.button-group.button-large .button {
+.wp-core-ui .button.button-large,
+.wp-core-ui .button-group.button-large .button {
 	height: 30px;
     line-height: 28px;
     padding: 0 12px 2px;
 }
 
-.button.button-small,
-.button-group.button-small .button {
+.wp-core-ui .button.button-small,
+.wp-core-ui .button-group.button-small .button {
 	height: 21px;
 	line-height: 20px;
 	padding: 0 8px 1px;
 }
 
-.button.button-hero,
-.button-group.button-hero .button {
+.wp-core-ui .button.button-hero,
+.wp-core-ui .button-group.button-hero .button {
 	font-size: 14px;
 	height: 46px;
 	line-height: 44px;
 	padding: 0 36px;
 }
 
-.button:active {
+.wp-core-ui .button:active {
 	outline: none;
 }
 
-.button.hidden {
+.wp-core-ui .button.hidden {
 	display: none;
 }
 
@@ -101,8 +101,8 @@
   2.0 - Default Button Style
 ---------------------------------------------------------------------------- */
 
-.button,
-.button-secondary {
+.wp-core-ui .button,
+.wp-core-ui .button-secondary {
 	background: #f3f3f3;
 	background-image: -webkit-gradient(linear, left top, left bottom, from(#fefefe), to(#f4f4f4));
 	background-image: -webkit-linear-gradient(top, #fefefe, #f4f4f4);
@@ -114,12 +114,12 @@
 	text-shadow: 0 1px 0 #fff;
 }
 
-.button.hover,
-.button:hover,
-.button-secondary:hover,
-.button.focus,
-.button:focus,
-.button-secondary:focus {
+.wp-core-ui .button.hover,
+.wp-core-ui .button:hover,
+.wp-core-ui .button-secondary:hover,
+.wp-core-ui .button.focus,
+.wp-core-ui .button:focus,
+.wp-core-ui .button-secondary:focus {
 	background: #f3f3f3;
 	background-image: -webkit-gradient(linear, left top, left bottom, from(#fff), to(#f3f3f3));
 	background-image: -webkit-linear-gradient(top, #fff, #f3f3f3);
@@ -131,18 +131,18 @@
 	color: #222;
 }
 
-.button.focus,
-.button:focus,
-.button-secondary:focus {
+.wp-core-ui .button.focus,
+.wp-core-ui .button:focus,
+.wp-core-ui .button-secondary:focus {
 	-webkit-box-shadow: 1px 1px 1px rgba(0,0,0,.2);
 	box-shadow: 1px 1px 1px rgba(0,0,0,.2);
 }
 
-.button.active,
-.button.active:hover,
-.button.active:focus,
-.button:active,
-.button-secondary:active {
+.wp-core-ui .button.active,
+.wp-core-ui .button.active:hover,
+.wp-core-ui .button.active:focus,
+.wp-core-ui .button:active,
+.wp-core-ui .button-secondary:active {
 	background: #eee;
 	background-image: -webkit-gradient(linear, left top, left bottom, from(#f4f4f4), to(#fefefe));
 	background-image: -webkit-linear-gradient(top, #f4f4f4, #fefefe);
@@ -157,11 +157,11 @@
  	box-shadow: inset 0 2px 5px -3px rgba( 0, 0, 0, 0.5 );
 }
 
-.button[disabled],
-.button:disabled,
-.button-secondary[disabled],
-.button-secondary:disabled,
-.button-disabled {
+.wp-core-ui .button[disabled],
+.wp-core-ui .button:disabled,
+.wp-core-ui .button-secondary[disabled],
+.wp-core-ui .button-secondary:disabled,
+.wp-core-ui .button-disabled {
 	color: #aaa !important;
 	border-color: #ddd !important;
 	background-image: -webkit-gradient(linear, left top, left bottom, from(#f9f9f9), to(#f4f4f4)) !important;
@@ -180,7 +180,7 @@
   3.0 - Primary Button Style
 ---------------------------------------------------------------------------- */
 
-.button-primary {
+.wp-core-ui .button-primary {
 	background-color: #21759b;
 	background-image: -webkit-gradient(linear, left top, left bottom, from(#2a95c5), to(#21759b));
 	background-image: -webkit-linear-gradient(top, #2a95c5, #21759b);
@@ -197,10 +197,10 @@
 	text-shadow: 0 1px 0 rgba(0,0,0,0.1);
 }
 
-.button-primary.hover,
-.button-primary:hover,
-.button-primary.focus,
-.button-primary:focus {
+.wp-core-ui .button-primary.hover,
+.wp-core-ui .button-primary:hover,
+.wp-core-ui .button-primary.focus,
+.wp-core-ui .button-primary:focus {
 	background-color: #278ab7;
 	background-image: -webkit-gradient(linear, left top, left bottom, from(#2e9fd2), to(#21759b));
 	background-image: -webkit-linear-gradient(top, #2e9fd2, #21759b);
@@ -215,17 +215,17 @@
 	text-shadow: 0 -1px 0 rgba(0,0,0,0.3);
 }
 
-.button-primary.focus,
-.button-primary:focus {
+.wp-core-ui .button-primary.focus,
+.wp-core-ui .button-primary:focus {
 	border-color: #0e3950;
 	-webkit-box-shadow: inset 0 1px 0 rgba(120,200,230,0.6), 1px 1px 2px rgba(0,0,0,0.4);
 	box-shadow: inset 0 1px 0 rgba(120,200,230,0.6), 1px 1px 2px rgba(0,0,0,0.4);
 }
 
-.button-primary.active,
-.button-primary.active:hover,
-.button-primary.active:focus,
-.button-primary:active {
+.wp-core-ui .button-primary.active,
+.wp-core-ui .button-primary.active:hover,
+.wp-core-ui .button-primary.active:focus,
+.wp-core-ui .button-primary:active {
 	background: #1b607f;
 	background-image: -webkit-gradient(linear, left top, left bottom, from(#21759b), to(#278ab7));
 	background-image: -webkit-linear-gradient(top, #21759b, #278ab7);
@@ -240,9 +240,9 @@
 	text-shadow: 0 1px 0 rgba(0,0,0,0.1);
 }
 
-.button-primary[disabled],
-.button-primary:disabled,
-.button-primary-disabled {
+.wp-core-ui .button-primary[disabled],
+.wp-core-ui .button-primary:disabled,
+.wp-core-ui .button-primary-disabled {
 	color: #94cde7 !important;
 	background: #298cba !important;
 	border-color: #1b607f !important;
@@ -256,7 +256,7 @@
   4.0 - Button Groups
 ---------------------------------------------------------------------------- */
 
-.button-group {
+.wp-core-ui .button-group {
 	position: relative;
 	display: inline-block;
 	white-space: nowrap;
@@ -264,25 +264,25 @@
 	vertical-align: middle;
 }
 
-.button-group > .button {
+.wp-core-ui .button-group > .button {
 	display: inline-block;
 	border-radius: 0;
 	margin-right: -1px;
 	z-index: 10;
 }
 
-.button-group > .button-primary {
+.wp-core-ui .button-group > .button-primary {
 	z-index: 100;
 }
 
-.button-group > .button:hover {
+.wp-core-ui .button-group > .button:hover {
 	z-index: 20;
 }
 
-.button-group > .button:first-child {
+.wp-core-ui .button-group > .button:first-child {
 	border-radius: 3px 0 0 3px;
 }
 
-.button-group > .button:last-child {
+.wp-core-ui .button-group > .button:last-child {
 	border-radius: 0 3px 3px 0;
 }
Index: wp-includes/js/media-views.js
===================================================================
--- wp-includes/js/media-views.js	(revision 22944)
+++ wp-includes/js/media-views.js	(working copy)
@@ -1099,6 +1099,9 @@
 				uploader: true
 			});
 
+			// Ensure core UI is enabled.
+			this.$el.addClass('wp-core-ui');
+
 			// Initialize modal container view.
 			if ( this.options.modal ) {
 				this.modal = new media.view.Modal({
Index: wp-includes/js/tinymce/plugins/wpeditimage/editimage.html
===================================================================
--- wp-includes/js/tinymce/plugins/wpeditimage/editimage.html	(revision 22944)
+++ wp-includes/js/tinymce/plugins/wpeditimage/editimage.html	(working copy)
@@ -11,7 +11,7 @@
 <base target="_self" />
 </head>
 
-<body id="media-upload" style="display:none;">
+<body id="media-upload" class="wp-core-ui" style="display:none;">
 <script type="text/javascript">
 if ( 'rtl' == tinyMCEPopup.editor.getParam('directionality','') )
 	document.body.className += ' rtl';
Index: wp-includes/js/tinymce/wp-mce-help.php
===================================================================
--- wp-includes/js/tinymce/wp-mce-help.php	(revision 22944)
+++ wp-includes/js/tinymce/wp-mce-help.php	(working copy)
@@ -152,7 +152,7 @@
 </style>
 <?php endif; ?>
 </head>
-<body class="windows">
+<body class="windows wp-core-ui">
 <script type="text/javascript">
 if ( tinymce.isMac )
 	document.body.className = document.body.className.replace(/windows/, 'macos');
Index: wp-includes/media.php
===================================================================
--- wp-includes/media.php	(revision 22944)
+++ wp-includes/media.php	(working copy)
@@ -1505,7 +1505,7 @@
 	</script>
 
 	<script type="text/html" id="tmpl-media-modal">
-		<div class="media-modal">
+		<div class="media-modal wp-core-ui">
 			<h3 class="media-modal-title">{{ data.title }}</h3>
 			<a class="media-modal-close media-modal-icon" href="#" title="<?php esc_attr_e('Close'); ?>"></a>
 		</div>
Index: wp-login.php
===================================================================
--- wp-login.php	(revision 22944)
+++ wp-login.php	(working copy)
@@ -86,7 +86,7 @@
 	if ( $interim_login )
 		$login_header_url = '#';
 
-	$classes = array( 'login-action-' . $action );
+	$classes = array( 'login-action-' . $action, 'wp-core-ui' );
 	if ( wp_is_mobile() )
 		$classes[] = 'mobile';
 	if ( is_rtl() )
