Index: wp-admin/customize.php
===================================================================
--- wp-admin/customize.php	(revision 28867)
+++ wp-admin/customize.php	(working copy)
@@ -108,8 +108,8 @@
 				submit_button( $save_text, 'primary save', 'save', false );
 			?>
 			<span class="spinner"></span>
-			<a class="back button" href="<?php echo esc_url( $return ? $return : admin_url( 'themes.php' ) ); ?>">
-				<?php _e( 'Cancel' ); ?>
+			<a class="back customize-controls-close" href="<?php echo esc_url( $return ? $return : admin_url( 'themes.php' ) ); ?>">
+				<?php _e( 'Cancel' ); ?></span>
 			</a>
 		</div>
 
Index: wp-admin/css/customize-controls.css
===================================================================
--- wp-admin/css/customize-controls.css	(revision 28867)
+++ wp-admin/css/customize-controls.css	(working copy)
@@ -211,18 +211,51 @@
 
 #customize-header-actions a.back {
 	position: relative;
+	left: 0px;
+	top: -100px;
+	color: transparent;
+	-webkit-transition: left ease-in-out .18s;
+	transition: left ease-in-out .18s;
+}
+
+
+#customize-header-actions .customize-controls-close {
+	position: relative;
 	left: 0;
 	-webkit-transition: left ease-in-out .18s;
 	transition: left ease-in-out .18s;
 }
 
-.in-sub-panel #customize-header-actions a.back {
+.customize-controls-close:before {
+	font: normal 30px/1.5 dashicons;
+	color: #000;
+	width:30px;
+	padding: 9px 9px 7.5px 9px;  
+ 	content: "\f335";  
+ 	position: relative; 
+ 	visibility: visible;
+	top: 100px;
+	border-right: 1px solid #ddd;
+}
+
+.customize-controls-close:hover::before {  
+	background-color: #0074a2;  
+	color: #fff;  
+ 	outline: none; 
+}  
+
+.in-sub-panel #customize-header-actions a.back {	
 	left: -120px;
 }
 
+.in-sub-panel #customize-header-actions .customize-controls-close:before {	
+	left: -120px;
+}
+
 .wp-full-overlay-sidebar .wp-full-overlay-header {
 	-webkit-transition: padding ease-in-out .18s;
 	transition: padding ease-in-out .18s;
+	padding: 0 15px 0 0;
 }
 
 .in-sub-panel .wp-full-overlay-sidebar .wp-full-overlay-header {