Index: src/wp-content/themes/twentyfifteen/js/color-scheme-control.js
===================================================================
--- src/wp-content/themes/twentyfifteen/js/color-scheme-control.js	(revision 30088)
+++ src/wp-content/themes/twentyfifteen/js/color-scheme-control.js	(working copy)
@@ -1,8 +1,6 @@
 /* global colorScheme */
 /**
- * Customizer enhancements for a better user experience.
- *
- * Adds listener to Color Scheme control to update other color controls with new values/defaults
+ * Add a listener to the Color Scheme control to update other color controls to new values/defaults.
  */
 
 ( function( wp ) {
@@ -16,7 +14,7 @@
 					sidebarTextColor = parentSection.find( '#customize-control-sidebar_textcolor .color-picker-hex' );
 
 				this.setting.bind( 'change', function( value ) {
-					// if Header Text is not hidden, update value
+					// If Header Text is not hidden, update value.
 					if ( 'blank' !== wp.customize( 'header_textcolor' ).get() ) {
 						wp.customize( 'header_textcolor' ).set( colorScheme[value].colors[4] );
 						headerTextColor.val( colorScheme[value].colors[4] )
@@ -25,7 +23,7 @@
 							.wpColorPicker( 'defaultColor', colorScheme[value].colors[4] );
 					}
 
-					// update Background Color
+					// Update Background Color.
 					wp.customize( 'background_color' ).set( colorScheme[value].colors[0] );
 					backgroundColor.val( colorScheme[value].colors[0] )
 						.data( 'data-default-color', colorScheme[value].colors[0] )
@@ -32,7 +30,7 @@
 						.wpColorPicker( 'color', colorScheme[value].colors[0] )
 						.wpColorPicker( 'defaultColor', colorScheme[value].colors[0] );
 
-					// update Header/Sidebar Background Color
+					// Update Header/Sidebar Background Color.
 					wp.customize( 'header_background_color' ).set( colorScheme[value].colors[1] );
 					sidebarColor.val( colorScheme[value].colors[1] )
 						.data( 'data-default-color', colorScheme[value].colors[1] )
@@ -39,7 +37,7 @@
 						.wpColorPicker( 'color', colorScheme[value].colors[1] )
 						.wpColorPicker( 'defaultColor', colorScheme[value].colors[1] );
 
-					// update Sidebar Text Color
+					// Update Sidebar Text Color.
 					wp.customize( 'sidebar_textcolor' ).set( colorScheme[value].colors[4] );
 					sidebarTextColor.val( colorScheme[value].colors[4] )
 						.data( 'data-default-color', colorScheme[value].colors[4] )
Index: src/wp-content/themes/twentyfifteen/js/customize-preview.js
===================================================================
--- src/wp-content/themes/twentyfifteen/js/customize-preview.js	(revision 0)
+++ src/wp-content/themes/twentyfifteen/js/customize-preview.js	(working copy)
@@ -0,0 +1,17 @@
+/**
+ * Live-update changed settings in real time in the Customizer preview.
+ */
+
+( function( $ ) {
+	// Site title and description.
+	wp.customize( 'blogname', function( value ) {
+		value.bind( function( to ) {
+			$( '.site-title a' ).text( to );
+		} );
+	} );
+	wp.customize( 'blogdescription', function( value ) {
+		value.bind( function( to ) {
+			$( '.site-description' ).text( to );
+		} );
+	} );
+} )( jQuery );
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