Index: src/wp-content/themes/twentyfifteen/inc/customizer.php
===================================================================
--- src/wp-content/themes/twentyfifteen/inc/customizer.php	(revision 30625)
+++ src/wp-content/themes/twentyfifteen/inc/customizer.php	(working copy)
@@ -49,7 +49,7 @@
 
 	$wp_customize->add_control( new WP_Customize_Color_Control( $wp_customize, 'sidebar_textcolor', array(
 		'label'       => esc_html__( 'Header and Sidebar Text Color', 'twentyfifteen' ),
-		'description' => esc_html__( 'Only applied to the sidebar on wider screens. On small screens the sidebar will become the header.', 'twentyfifteen' ),
+		'description' => esc_html__( 'Only applied to the sidebar on wide screens. On small screens it will be applied to the header.', 'twentyfifteen' ),
 		'section'     => 'colors',
 	) ) );
 
@@ -65,7 +65,7 @@
 
 	$wp_customize->add_control( new WP_Customize_Color_Control( $wp_customize, 'header_background_color', array(
 		'label'       => esc_html__( 'Header and Sidebar Background Color', 'twentyfifteen' ),
-		'description' => esc_html__( 'Only applied to the sidebar on wider screens. On small screens the sidebar will become the header.', 'twentyfifteen' ),
+		'description' => esc_html__( 'Only applied to the sidebar on wide screens. On small screens it will be applied to the header.', 'twentyfifteen' ),
 		'section'     => 'colors',
 	) ) );