diff --git a/src/wp-admin/css/customize-controls.css b/src/wp-admin/css/customize-controls.css
index 3f2193b286..04e0b54798 100644
--- a/src/wp-admin/css/customize-controls.css
+++ b/src/wp-admin/css/customize-controls.css
@@ -1204,7 +1204,7 @@ body.cheatin p {
  * Widgets and Menus common styles
  */
 
-/* higher specificity than .wp-core-ui .button-secondary */
+/* higher specificity than .wp-core-ui .button */
 #customize-theme-controls .add-new-widget,
 #customize-theme-controls .add-new-menu-item {
 	cursor: pointer;
diff --git a/src/wp-admin/css/ie.css b/src/wp-admin/css/ie.css
index 90cf8f341c..d98f31bbcc 100644
--- a/src/wp-admin/css/ie.css
+++ b/src/wp-admin/css/ie.css
@@ -221,8 +221,7 @@ table.fixed td {
 }
 
 #wpbody-content input.button,
-#wpbody-content input.button-primary,
-#wpbody-content input.button-secondary {
+#wpbody-content input.button-primary {
 	overflow: visible;
 }
 
@@ -447,8 +446,8 @@ div#dashboard-widgets {
 	display: block;
 }
 
-.tablenav .button-secondary,
-.nav .button-secondary {
+.tablenav .button,
+.nav .button {
 	padding-top: 2px;
 	padding-bottom: 2px;
 }
@@ -507,7 +506,7 @@ table.ie-fixed {
 	border-collapse: collapse;
 }
 
-.tablenav a.button-secondary {
+.tablenav a.button {
 	display: inline-block;
 	padding: 2px 5px;
 }
diff --git a/src/wp-admin/css/install.css b/src/wp-admin/css/install.css
index d1db4ec661..9de99ee366 100644
--- a/src/wp-admin/css/install.css
+++ b/src/wp-admin/css/install.css
@@ -443,7 +443,7 @@ body.language-chooser {
 	margin-right: 15px;
 }
 
-.button-secondary.hide-if-no-js,
+.button.hide-if-no-js,
 .hide-if-no-js {
 	display: none;
 }
diff --git a/src/wp-admin/css/list-tables.css b/src/wp-admin/css/list-tables.css
index b66f0c0d84..67ef22e183 100644
--- a/src/wp-admin/css/list-tables.css
+++ b/src/wp-admin/css/list-tables.css
@@ -656,6 +656,7 @@ th.asc a:focus span.sorting-indicator {
 	margin-left: 2px;
 }
 
+.tablenav a.button,
 .tablenav a.button-secondary {
 	display: block;
 	margin: 3px 8px 0 0;
diff --git a/src/wp-admin/css/themes.css b/src/wp-admin/css/themes.css
index d4a7bcf624..857f14dc1a 100644
--- a/src/wp-admin/css/themes.css
+++ b/src/wp-admin/css/themes.css
@@ -114,7 +114,7 @@
 	margin-right: 3px;
 }
 
-.theme-browser .theme .theme-actions .button-secondary {
+.theme-browser .theme .theme-actions .button {
 	float: none;
 	margin-left: 3px;
 }
diff --git a/src/wp-admin/custom-background.php b/src/wp-admin/custom-background.php
index a03986f594..9626c291a0 100644
--- a/src/wp-admin/custom-background.php
+++ b/src/wp-admin/custom-background.php
@@ -242,7 +242,7 @@ class Custom_Background {
 <td>
 <form method="post">
 <?php wp_nonce_field('custom-background-remove', '_wpnonce-custom-background-remove'); ?>
-<?php submit_button( __( 'Remove Background Image' ), 'button', 'remove-background', false ); ?><br/>
+<?php submit_button( __( 'Remove Background Image' ), '', 'remove-background', false ); ?><br/>
 <?php _e('This will remove the background image. You will not be able to restore any customizations.') ?>
 </form>
 </td>
@@ -256,7 +256,7 @@ class Custom_Background {
 <td>
 <form method="post">
 <?php wp_nonce_field('custom-background-reset', '_wpnonce-custom-background-reset'); ?>
-<?php submit_button( __( 'Restore Original Image' ), 'button', 'reset-background', false ); ?><br/>
+<?php submit_button( __( 'Restore Original Image' ), '', 'reset-background', false ); ?><br/>
 <?php _e('This will restore the original background image. You will not be able to restore any customizations.') ?>
 </form>
 </td>
@@ -272,7 +272,7 @@ class Custom_Background {
 		<input type="file" id="upload" name="import" />
 		<input type="hidden" name="action" value="save" />
 		<?php wp_nonce_field( 'custom-background-upload', '_wpnonce-custom-background-upload' ); ?>
-		<?php submit_button( __( 'Upload' ), 'button', 'submit', false ); ?>
+		<?php submit_button( __( 'Upload' ), '', 'submit', false ); ?>
 	</p>
 	<p>
 		<label for="choose-from-library-link"><?php _e( 'Or choose an image from your media library:' ); ?></label><br />
diff --git a/src/wp-admin/custom-header.php b/src/wp-admin/custom-header.php
index fc5adb670e..c339498c11 100644
--- a/src/wp-admin/custom-header.php
+++ b/src/wp-admin/custom-header.php
@@ -576,7 +576,7 @@ class Custom_Image_Header {
 		<input type="file" id="upload" name="import" />
 		<input type="hidden" name="action" value="save" />
 		<?php wp_nonce_field( 'custom-header-upload', '_wpnonce-custom-header-upload' ); ?>
-		<?php submit_button( __( 'Upload' ), 'button', 'submit', false ); ?>
+		<?php submit_button( __( 'Upload' ), '', 'submit', false ); ?>
 	</p>
 	<?php
 		$modal_update_href = esc_url( add_query_arg( array(
@@ -634,7 +634,7 @@ class Custom_Image_Header {
 <th scope="row"><?php _e( 'Remove Image' ); ?></th>
 <td>
 	<p><?php _e( 'This will remove the header image. You will not be able to restore any customizations.' ) ?></p>
-	<?php submit_button( __( 'Remove Header Image' ), 'button', 'removeheader', false ); ?>
+	<?php submit_button( __( 'Remove Header Image' ), '', 'removeheader', false ); ?>
 </td>
 </tr>
 	<?php endif;
@@ -645,7 +645,7 @@ class Custom_Image_Header {
 <th scope="row"><?php _e( 'Reset Image' ); ?></th>
 <td>
 	<p><?php _e( 'This will restore the original header image. You will not be able to restore any customizations.' ) ?></p>
-	<?php submit_button( __( 'Restore Original Header Image' ), 'button', 'resetheader', false ); ?>
+	<?php submit_button( __( 'Restore Original Header Image' ), '', 'resetheader', false ); ?>
 </td>
 </tr>
 	<?php endif; ?>
@@ -823,7 +823,7 @@ wp_nonce_field( 'custom-header-options', '_wpnonce-custom-header-options' ); ?>
 	<?php submit_button( __( 'Crop and Publish' ), 'primary', 'submit', false ); ?>
 	<?php
 	if ( isset( $oitar ) && 1 == $oitar && ( current_theme_supports( 'custom-header', 'flex-height' ) || current_theme_supports( 'custom-header', 'flex-width' ) ) )
-		submit_button( __( 'Skip Cropping, Publish Image as Is' ), 'secondary', 'skip-cropping', false );
+		submit_button( __( 'Skip Cropping, Publish Image as Is' ), '', 'skip-cropping', false );
 	?>
 	</p>
 </form>
diff --git a/src/wp-admin/customize.php b/src/wp-admin/customize.php
index 6c0b20d6c2..e45254c74a 100644
--- a/src/wp-admin/customize.php
+++ b/src/wp-admin/customize.php
@@ -168,7 +168,7 @@ do_action( 'customize_controls_print_scripts' );
 				<?php endforeach; ?>
 			</div>
 			<?php endif; ?>
-			<button type="button" class="collapse-sidebar button-secondary" aria-expanded="true" aria-label="<?php esc_attr_e( 'Collapse Sidebar' ); ?>">
+			<button type="button" class="collapse-sidebar button" aria-expanded="true" aria-label="<?php esc_attr_e( 'Collapse Sidebar' ); ?>">
 				<span class="collapse-sidebar-arrow"></span>
 				<span class="collapse-sidebar-label"><?php _e( 'Collapse' ); ?></span>
 			</button>
diff --git a/src/wp-admin/includes/class-wp-comments-list-table.php b/src/wp-admin/includes/class-wp-comments-list-table.php
index cb7801870d..37a2e751a9 100644
--- a/src/wp-admin/includes/class-wp-comments-list-table.php
+++ b/src/wp-admin/includes/class-wp-comments-list-table.php
@@ -351,7 +351,7 @@ class WP_Comments_List_Table extends WP_List_Table {
 			 * @since 3.5.0
 			 */
 			do_action( 'restrict_manage_comments' );
-			submit_button( __( 'Filter' ), 'button', 'filter_action', false, array( 'id' => 'post-query-submit' ) );
+			submit_button( __( 'Filter' ), '', 'filter_action', false, array( 'id' => 'post-query-submit' ) );
 		}
 
 		if ( ( 'spam' === $comment_status || 'trash' === $comment_status ) && current_user_can( 'moderate_comments' ) ) {
diff --git a/src/wp-admin/includes/class-wp-links-list-table.php b/src/wp-admin/includes/class-wp-links-list-table.php
index e4560e480f..222d6dfc2d 100644
--- a/src/wp-admin/includes/class-wp-links-list-table.php
+++ b/src/wp-admin/includes/class-wp-links-list-table.php
@@ -112,7 +112,7 @@ class WP_Links_List_Table extends WP_List_Table {
 
 			echo '<label class="screen-reader-text" for="cat_id">' . __( 'Filter by category' ) . '</label>';
 			wp_dropdown_categories( $dropdown_options );
-			submit_button( __( 'Filter' ), 'button', 'filter_action', false, array( 'id' => 'post-query-submit' ) );
+			submit_button( __( 'Filter' ), '', 'filter_action', false, array( 'id' => 'post-query-submit' ) );
 ?>
 		</div>
 <?php
diff --git a/src/wp-admin/includes/class-wp-list-table.php b/src/wp-admin/includes/class-wp-list-table.php
index 0ef4de35aa..bf642acb25 100644
--- a/src/wp-admin/includes/class-wp-list-table.php
+++ b/src/wp-admin/includes/class-wp-list-table.php
@@ -361,7 +361,7 @@ class WP_List_Table {
 <p class="search-box">
 	<label class="screen-reader-text" for="<?php echo esc_attr( $input_id ); ?>"><?php echo $text; ?>:</label>
 	<input type="search" id="<?php echo esc_attr( $input_id ); ?>" name="s" value="<?php _admin_search_query(); ?>" />
-	<?php submit_button( $text, 'button', '', false, array( 'id' => 'search-submit' ) ); ?>
+	<?php submit_button( $text, '', '', false, array( 'id' => 'search-submit' ) ); ?>
 </p>
 <?php
 	}
diff --git a/src/wp-admin/includes/class-wp-media-list-table.php b/src/wp-admin/includes/class-wp-media-list-table.php
index 170ec5a2c5..233ca6ebf4 100644
--- a/src/wp-admin/includes/class-wp-media-list-table.php
+++ b/src/wp-admin/includes/class-wp-media-list-table.php
@@ -174,7 +174,7 @@ class WP_Media_List_Table extends WP_List_Table {
 			/** This action is documented in wp-admin/includes/class-wp-posts-list-table.php */
 			do_action( 'restrict_manage_posts', $this->screen->post_type );
 
-			submit_button( __( 'Filter' ), 'button', 'filter_action', false, array( 'id' => 'post-query-submit' ) );
+			submit_button( __( 'Filter' ), '', 'filter_action', false, array( 'id' => 'post-query-submit' ) );
 		}
 
 		if ( $this->is_trash && current_user_can( 'edit_others_posts' ) ) {
diff --git a/src/wp-admin/includes/class-wp-plugin-install-list-table.php b/src/wp-admin/includes/class-wp-plugin-install-list-table.php
index 73df40f8f1..475c95e8af 100644
--- a/src/wp-admin/includes/class-wp-plugin-install-list-table.php
+++ b/src/wp-admin/includes/class-wp-plugin-install-list-table.php
@@ -488,7 +488,7 @@ class WP_Plugin_Install_List_Table extends WP_List_Table {
 							}
 
 							$action_links[] = sprintf(
-								'<a href="%1$s" class="button activate-now button-secondary" aria-label="%2$s">%3$s</a>',
+								'<a href="%1$s" class="button activate-now" aria-label="%2$s">%3$s</a>',
 								esc_url( $activate_url ),
 								esc_attr( sprintf( $button_label, $plugin['name'] ) ),
 								$button_text
diff --git a/src/wp-admin/includes/class-wp-plugins-list-table.php b/src/wp-admin/includes/class-wp-plugins-list-table.php
index a8783f552d..7e2a3d339b 100644
--- a/src/wp-admin/includes/class-wp-plugins-list-table.php
+++ b/src/wp-admin/includes/class-wp-plugins-list-table.php
@@ -367,7 +367,7 @@ class WP_Plugins_List_Table extends WP_List_Table {
 		<p class="search-box">
 			<label class="screen-reader-text" for="<?php echo esc_attr( $input_id ); ?>"><?php echo $text; ?>:</label>
 			<input type="search" id="<?php echo esc_attr( $input_id ); ?>" class="wp-filter-search" name="s" value="<?php _admin_search_query(); ?>" placeholder="<?php esc_attr_e( 'Search installed plugins...' ); ?>"/>
-			<?php submit_button( $text, 'button hide-if-js', '', false, array( 'id' => 'search-submit' ) ); ?>
+			<?php submit_button( $text, 'hide-if-js', '', false, array( 'id' => 'search-submit' ) ); ?>
 		</p>
 		<?php
 	}
@@ -496,7 +496,7 @@ class WP_Plugins_List_Table extends WP_List_Table {
 		echo '<div class="alignleft actions">';
 
 		if ( 'recently_activated' == $status ) {
-			submit_button( __( 'Clear List' ), 'button', 'clear-recent-list', false );
+			submit_button( __( 'Clear List' ), '', 'clear-recent-list', false );
 		} elseif ( 'top' === $which && 'mustuse' === $status ) {
 			/* translators: %s: mu-plugins directory name */
 			echo '<p>' . sprintf( __( 'Files in the %s directory are executed automatically.' ),
diff --git a/src/wp-admin/includes/class-wp-posts-list-table.php b/src/wp-admin/includes/class-wp-posts-list-table.php
index 7ef790e31a..506dded3fd 100644
--- a/src/wp-admin/includes/class-wp-posts-list-table.php
+++ b/src/wp-admin/includes/class-wp-posts-list-table.php
@@ -479,7 +479,7 @@ class WP_Posts_List_Table extends WP_List_Table {
 			 */
 			do_action( 'restrict_manage_posts', $this->screen->post_type, $which );
 
-			submit_button( __( 'Filter' ), 'button', 'filter_action', false, array( 'id' => 'post-query-submit' ) );
+			submit_button( __( 'Filter' ), '', 'filter_action', false, array( 'id' => 'post-query-submit' ) );
 		}
 
 		if ( $this->is_trash && current_user_can( get_post_type_object( $this->screen->post_type )->cap->edit_others_posts ) ) {
@@ -1713,14 +1713,14 @@ class WP_Posts_List_Table extends WP_List_Table {
 		}
 	?>
 		<p class="submit inline-edit-save">
-			<button type="button" class="button-secondary cancel alignleft"><?php _e( 'Cancel' ); ?></button>
+			<button type="button" class="button cancel alignleft"><?php _e( 'Cancel' ); ?></button>
 			<?php if ( ! $bulk ) {
 				wp_nonce_field( 'inlineeditnonce', '_inline_edit', false );
 				?>
-				<button type="button" class="button-primary save alignright"><?php _e( 'Update' ); ?></button>
+				<button type="button" class="button button-primary save alignright"><?php _e( 'Update' ); ?></button>
 				<span class="spinner"></span>
 			<?php } else {
-				submit_button( __( 'Update' ), 'button-primary alignright', 'bulk_edit', false );
+				submit_button( __( 'Update' ), 'primary alignright', 'bulk_edit', false );
 			} ?>
 			<input type="hidden" name="post_view" value="<?php echo esc_attr( $m ); ?>" />
 			<input type="hidden" name="screen" value="<?php echo esc_attr( $screen->id ); ?>" />
diff --git a/src/wp-admin/includes/class-wp-terms-list-table.php b/src/wp-admin/includes/class-wp-terms-list-table.php
index 6e9f9c65ae..257c44a64c 100644
--- a/src/wp-admin/includes/class-wp-terms-list-table.php
+++ b/src/wp-admin/includes/class-wp-terms-list-table.php
@@ -619,8 +619,8 @@ class WP_Terms_List_Table extends WP_List_Table {
 	?>
 
 		<p class="inline-edit-save submit">
-			<button type="button" class="cancel button-secondary alignleft"><?php _e( 'Cancel' ); ?></button>
-			<button type="button" class="save button-primary alignright"><?php echo $tax->labels->update_item; ?></button>
+			<button type="button" class="cancel button alignleft"><?php _e( 'Cancel' ); ?></button>
+			<button type="button" class="save button button-primary alignright"><?php echo $tax->labels->update_item; ?></button>
 			<span class="spinner"></span>
 			<span class="error" style="display:none;"></span>
 			<?php wp_nonce_field( 'taxinlineeditnonce', '_inline_edit', false ); ?>
diff --git a/src/wp-admin/includes/class-wp-theme-install-list-table.php b/src/wp-admin/includes/class-wp-theme-install-list-table.php
index 3388732a0f..feb5b9976c 100644
--- a/src/wp-admin/includes/class-wp-theme-install-list-table.php
+++ b/src/wp-admin/includes/class-wp-theme-install-list-table.php
@@ -329,14 +329,14 @@ class WP_Theme_Install_List_Table extends WP_Themes_List_Table {
 		<div id="theme-installer" class="wp-full-overlay expanded">
 			<div class="wp-full-overlay-sidebar">
 				<div class="wp-full-overlay-header">
-					<a href="#" class="close-full-overlay button-secondary"><?php _e( 'Close' ); ?></a>
+					<a href="#" class="close-full-overlay button"><?php _e( 'Close' ); ?></a>
 					<span class="theme-install"></span>
 				</div>
 				<div class="wp-full-overlay-sidebar-content">
 					<div class="install-theme-info"></div>
 				</div>
 				<div class="wp-full-overlay-footer">
-					<button type="button" class="collapse-sidebar button-secondary" aria-expanded="true" aria-label="<?php esc_attr_e( 'Collapse Sidebar' ); ?>">
+					<button type="button" class="collapse-sidebar button" aria-expanded="true" aria-label="<?php esc_attr_e( 'Collapse Sidebar' ); ?>">
 						<span class="collapse-sidebar-arrow"></span>
 						<span class="collapse-sidebar-label"><?php _e( 'Collapse' ); ?></span>
 					</button>
@@ -398,7 +398,7 @@ class WP_Theme_Install_List_Table extends WP_Themes_List_Table {
 		<div class="install-theme-info"><?php
 			switch ( $status ) {
 				case 'update_available':
-					echo '<a class="theme-install button-primary" href="' . esc_url( wp_nonce_url( $update_url, 'upgrade-theme_' . $theme->slug ) ) . '" title="' . esc_attr( sprintf( __( 'Update to version %s' ), $theme->version ) ) . '">' . __( 'Update' ) . '</a>';
+					echo '<a class="theme-install button button-primary" href="' . esc_url( wp_nonce_url( $update_url, 'upgrade-theme_' . $theme->slug ) ) . '" title="' . esc_attr( sprintf( __( 'Update to version %s' ), $theme->version ) ) . '">' . __( 'Update' ) . '</a>';
 					break;
 				case 'newer_installed':
 				case 'latest_installed':
@@ -406,7 +406,7 @@ class WP_Theme_Install_List_Table extends WP_Themes_List_Table {
 					break;
 				case 'install':
 				default:
-					echo '<a class="theme-install button-primary" href="' . esc_url( wp_nonce_url( $install_url, 'install-theme_' . $theme->slug ) ) . '">' . __( 'Install' ) . '</a>';
+					echo '<a class="theme-install button button-primary" href="' . esc_url( wp_nonce_url( $install_url, 'install-theme_' . $theme->slug ) ) . '">' . __( 'Install' ) . '</a>';
 					break;
 			} ?>
 			<h3 class="theme-name"><?php echo $name; ?></h3>
diff --git a/src/wp-admin/includes/class-wp-users-list-table.php b/src/wp-admin/includes/class-wp-users-list-table.php
index 80720b6c0f..3b7795dfab 100644
--- a/src/wp-admin/includes/class-wp-users-list-table.php
+++ b/src/wp-admin/includes/class-wp-users-list-table.php
@@ -267,7 +267,7 @@ class WP_Users_List_Table extends WP_List_Table {
 			<?php wp_dropdown_roles(); ?>
 		</select>
 	<?php
-			submit_button( __( 'Change' ), 'button', 'changeit', false );
+			submit_button( __( 'Change' ), '', 'changeit', false );
 		endif;
 
 		/**
diff --git a/src/wp-admin/includes/dashboard.php b/src/wp-admin/includes/dashboard.php
index f3d2f797e4..659e0600d8 100644
--- a/src/wp-admin/includes/dashboard.php
+++ b/src/wp-admin/includes/dashboard.php
@@ -427,7 +427,7 @@ function wp_network_dashboard_right_now() {
 		<p>
 			<label class="screen-reader-text" for="search-users"><?php _e( 'Search Users' ); ?></label>
 			<input type="search" name="s" value="" size="30" autocomplete="off" id="search-users"/>
-			<?php submit_button( __( 'Search Users' ), 'button', false, false, array( 'id' => 'submit_users' ) ); ?>
+			<?php submit_button( __( 'Search Users' ), '', false, false, array( 'id' => 'submit_users' ) ); ?>
 		</p>
 	</form>
 
@@ -435,7 +435,7 @@ function wp_network_dashboard_right_now() {
 		<p>
 			<label class="screen-reader-text" for="search-sites"><?php _e( 'Search Sites' ); ?></label>
 			<input type="search" name="s" value="" size="30" autocomplete="off" id="search-sites"/>
-			<?php submit_button( __( 'Search Sites' ), 'button', false, false, array( 'id' => 'submit_sites' ) ); ?>
+			<?php submit_button( __( 'Search Sites' ), '', false, false, array( 'id' => 'submit_sites' ) ); ?>
 		</p>
 	</form>
 <?php
diff --git a/src/wp-admin/includes/file.php b/src/wp-admin/includes/file.php
index 245acf3f16..079e1ae892 100644
--- a/src/wp-admin/includes/file.php
+++ b/src/wp-admin/includes/file.php
@@ -1261,7 +1261,7 @@ foreach ( (array) $extra_fields as $field ) {
 ?>
 	<p class="request-filesystem-credentials-action-buttons">
 		<button class="button cancel-button" data-js-action="close" type="button"><?php _e( 'Cancel' ); ?></button>
-		<?php submit_button( __( 'Proceed' ), 'button', 'upgrade', false ); ?>
+		<?php submit_button( __( 'Proceed' ), '', 'upgrade', false ); ?>
 	</p>
 </div>
 </form>
diff --git a/src/wp-admin/includes/media.php b/src/wp-admin/includes/media.php
index 1405e85334..9d63694031 100644
--- a/src/wp-admin/includes/media.php
+++ b/src/wp-admin/includes/media.php
@@ -1480,7 +1480,7 @@ function get_media_item( $attachment_id, $args = null ) {
 	);
 
 	if ( $r['send'] ) {
-		$r['send'] = get_submit_button( __( 'Insert into Post' ), 'button', "send[$attachment_id]", false );
+		$r['send'] = get_submit_button( __( 'Insert into Post' ), '', "send[$attachment_id]", false );
 	}
 
 	$delete = empty( $r['delete'] ) ? '' : $r['delete'];
@@ -2031,7 +2031,7 @@ if ( $id ) {
 ?></div>
 
 <p class="savebutton ml-submit">
-<?php submit_button( __( 'Save all changes' ), 'button', 'save', false ); ?>
+<?php submit_button( __( 'Save all changes' ), '', 'save', false ); ?>
 </p>
 </form>
 <?php
@@ -2242,7 +2242,7 @@ jQuery(function($){
 </div>
 
 <p class="ml-submit">
-<?php submit_button( __( 'Save all changes' ), 'button savebutton', 'save', false, array( 'id' => 'save-all', 'style' => 'display: none;' ) ); ?>
+<?php submit_button( __( 'Save all changes' ), 'savebutton', 'save', false, array( 'id' => 'save-all', 'style' => 'display: none;' ) ); ?>
 <input type="hidden" name="post_id" id="post_id" value="<?php echo (int) $post_id; ?>" />
 <input type="hidden" name="type" value="<?php echo esc_attr( $GLOBALS['type'] ); ?>" />
 <input type="hidden" name="tab" value="<?php echo esc_attr( $GLOBALS['tab'] ); ?>" />
@@ -2382,7 +2382,7 @@ function media_upload_library_form($errors) {
 <p id="media-search" class="search-box">
 	<label class="screen-reader-text" for="media-search-input"><?php _e('Search Media');?>:</label>
 	<input type="search" id="media-search-input" name="s" value="<?php the_search_query(); ?>" />
-	<?php submit_button( __( 'Search Media' ), 'button', '', false ); ?>
+	<?php submit_button( __( 'Search Media' ), '', '', false ); ?>
 </p>
 
 <ul class="subsubsub">
@@ -2479,7 +2479,7 @@ foreach ($arc_result as $arc_row) {
 </select>
 <?php } ?>
 
-<?php submit_button( __( 'Filter &#187;' ), 'button', 'post-query-submit', false ); ?>
+<?php submit_button( __( 'Filter &#187;' ), '', 'post-query-submit', false ); ?>
 
 </div>
 
@@ -2509,7 +2509,7 @@ jQuery(function($){
 <?php echo get_media_items(null, $errors); ?>
 </div>
 <p class="ml-submit">
-<?php submit_button( __( 'Save all changes' ), 'button savebutton', 'save', false ); ?>
+<?php submit_button( __( 'Save all changes' ), 'savebutton', 'save', false ); ?>
 <input type="hidden" name="post_id" id="post_id" value="<?php echo (int) $post_id; ?>" />
 </p>
 </form>
@@ -2612,7 +2612,7 @@ function wp_media_insert_url_form( $default_view = 'image' ) {
 		<tr class="not-image">
 			<td></td>
 			<td>
-				' . get_submit_button( __( 'Insert into Post' ), 'button', 'insertonlybutton', false ) . '
+				' . get_submit_button( __( 'Insert into Post' ), '', 'insertonlybutton', false ) . '
 			</td>
 		</tr>
 	</tbody></table>
diff --git a/src/wp-admin/includes/meta-boxes.php b/src/wp-admin/includes/meta-boxes.php
index 2d12faf46a..af1ee22136 100644
--- a/src/wp-admin/includes/meta-boxes.php
+++ b/src/wp-admin/includes/meta-boxes.php
@@ -32,7 +32,7 @@ function post_submit_meta_box( $post, $args = array() ) {
 
 <?php // Hidden submit button early on so that the browser chooses the right button when form is submitted with Return key ?>
 <div style="display:none;">
-<?php submit_button( __( 'Save' ), 'button', 'save' ); ?>
+<?php submit_button( __( 'Save' ), '', 'save' ); ?>
 </div>
 
 <div id="minor-publishing-actions">
@@ -290,7 +290,7 @@ function attachment_submit_meta_box( $post ) {
 
 <?php // Hidden submit button early on so that the browser chooses the right button when form is submitted with Return key ?>
 <div style="display:none;">
-<?php submit_button( __( 'Save' ), 'button', 'save' ); ?>
+<?php submit_button( __( 'Save' ), '', 'save' ); ?>
 </div>
 
 
@@ -875,7 +875,7 @@ function link_submit_meta_box($link) {
 
 <?php // Hidden submit button early on so that the browser chooses the right button when form is submitted with Return key ?>
 <div style="display:none;">
-<?php submit_button( __( 'Save' ), 'button', 'save', false ); ?>
+<?php submit_button( __( 'Save' ), '', 'save', false ); ?>
 </div>
 
 <div id="minor-publishing-actions">
diff --git a/src/wp-admin/includes/nav-menu.php b/src/wp-admin/includes/nav-menu.php
index 30f38e9f56..b1c6f647f2 100644
--- a/src/wp-admin/includes/nav-menu.php
+++ b/src/wp-admin/includes/nav-menu.php
@@ -284,7 +284,7 @@ function wp_nav_menu_item_link_meta_box() {
 
 		<p class="button-controls wp-clearfix">
 			<span class="add-to-menu">
-				<input type="submit"<?php wp_nav_menu_disabled_check( $nav_menu_selected_id ); ?> class="button-secondary submit-add-to-menu right" value="<?php esc_attr_e('Add to Menu'); ?>" name="add-custom-menu-item" id="submit-customlinkdiv" />
+				<input type="submit"<?php wp_nav_menu_disabled_check( $nav_menu_selected_id ); ?> class="button submit-add-to-menu right" value="<?php esc_attr_e('Add to Menu'); ?>" name="add-custom-menu-item" id="submit-customlinkdiv" />
 				<span class="spinner"></span>
 			</span>
 		</p>
@@ -450,7 +450,7 @@ function wp_nav_menu_item_post_type_meta_box( $object, $box ) {
 				<label for="quick-search-posttype-<?php echo $post_type_name; ?>" class="screen-reader-text"><?php _e( 'Search' ); ?></label>
 				<input type="search" class="quick-search" value="<?php echo $searched; ?>" name="quick-search-posttype-<?php echo $post_type_name; ?>" id="quick-search-posttype-<?php echo $post_type_name; ?>" />
 				<span class="spinner"></span>
-				<?php submit_button( __( 'Search' ), 'button-small quick-search-submit button-secondary hide-if-js', 'submit', false, array( 'id' => 'submit-quick-search-posttype-' . $post_type_name ) ); ?>
+				<?php submit_button( __( 'Search' ), 'small quick-search-submit hide-if-js', 'submit', false, array( 'id' => 'submit-quick-search-posttype-' . $post_type_name ) ); ?>
 			</p>
 
 			<ul id="<?php echo $post_type_name; ?>-search-checklist" data-wp-lists="list:<?php echo $post_type_name?>" class="categorychecklist form-no-clear">
@@ -572,7 +572,7 @@ function wp_nav_menu_item_post_type_meta_box( $object, $box ) {
 			</span>
 
 			<span class="add-to-menu">
-				<input type="submit"<?php wp_nav_menu_disabled_check( $nav_menu_selected_id ); ?> class="button-secondary submit-add-to-menu right" value="<?php esc_attr_e( 'Add to Menu' ); ?>" name="add-post-type-menu-item" id="<?php echo esc_attr( 'submit-posttype-' . $post_type_name ); ?>" />
+				<input type="submit"<?php wp_nav_menu_disabled_check( $nav_menu_selected_id ); ?> class="button submit-add-to-menu right" value="<?php esc_attr_e( 'Add to Menu' ); ?>" name="add-post-type-menu-item" id="<?php echo esc_attr( 'submit-posttype-' . $post_type_name ); ?>" />
 				<span class="spinner"></span>
 			</span>
 		</p>
@@ -739,7 +739,7 @@ function wp_nav_menu_item_taxonomy_meta_box( $object, $box ) {
 				<label for="quick-search-taxonomy-<?php echo $taxonomy_name; ?>" class="screen-reader-text"><?php _e( 'Search' ); ?></label>
 				<input type="search" class="quick-search" value="<?php echo $searched; ?>" name="quick-search-taxonomy-<?php echo $taxonomy_name; ?>" id="quick-search-taxonomy-<?php echo $taxonomy_name; ?>" />
 				<span class="spinner"></span>
-				<?php submit_button( __( 'Search' ), 'button-small quick-search-submit button-secondary hide-if-js', 'submit', false, array( 'id' => 'submit-quick-search-taxonomy-' . $taxonomy_name ) ); ?>
+				<?php submit_button( __( 'Search' ), 'small quick-search-submit hide-if-js', 'submit', false, array( 'id' => 'submit-quick-search-taxonomy-' . $taxonomy_name ) ); ?>
 			</p>
 
 			<ul id="<?php echo $taxonomy_name; ?>-search-checklist" data-wp-lists="list:<?php echo $taxonomy_name?>" class="categorychecklist form-no-clear">
@@ -770,7 +770,7 @@ function wp_nav_menu_item_taxonomy_meta_box( $object, $box ) {
 			</span>
 
 			<span class="add-to-menu">
-				<input type="submit"<?php wp_nav_menu_disabled_check( $nav_menu_selected_id ); ?> class="button-secondary submit-add-to-menu right" value="<?php esc_attr_e( 'Add to Menu' ); ?>" name="add-taxonomy-menu-item" id="<?php echo esc_attr( 'submit-taxonomy-' . $taxonomy_name ); ?>" />
+				<input type="submit"<?php wp_nav_menu_disabled_check( $nav_menu_selected_id ); ?> class="button submit-add-to-menu right" value="<?php esc_attr_e( 'Add to Menu' ); ?>" name="add-taxonomy-menu-item" id="<?php echo esc_attr( 'submit-taxonomy-' . $taxonomy_name ); ?>" />
 				<span class="spinner"></span>
 			</span>
 		</p>
diff --git a/src/wp-admin/includes/plugin-install.php b/src/wp-admin/includes/plugin-install.php
index a33797e540..10568b0158 100644
--- a/src/wp-admin/includes/plugin-install.php
+++ b/src/wp-admin/includes/plugin-install.php
@@ -265,7 +265,7 @@ function install_search_form( $deprecated = true ) {
 		<label><span class="screen-reader-text"><?php _e( 'Search Plugins' ); ?></span>
 			<input type="search" name="s" value="<?php echo esc_attr( $term ) ?>" class="wp-filter-search" placeholder="<?php esc_attr_e( 'Search Plugins' ); ?>" />
 		</label>
-		<?php submit_button( __( 'Search Plugins' ), 'button hide-if-js', false, false, array( 'id' => 'search-submit' ) ); ?>
+		<?php submit_button( __( 'Search Plugins' ), 'hide-if-js', false, false, array( 'id' => 'search-submit' ) ); ?>
 	</form><?php
 }
 
@@ -281,7 +281,7 @@ function install_plugins_upload() {
 		<?php wp_nonce_field( 'plugin-upload' ); ?>
 		<label class="screen-reader-text" for="pluginzip"><?php _e( 'Plugin zip file' ); ?></label>
 		<input type="file" id="pluginzip" name="pluginzip" />
-		<?php submit_button( __( 'Install Now' ), 'button', 'install-plugin-submit', false ); ?>
+		<?php submit_button( __( 'Install Now' ), '', 'install-plugin-submit', false ); ?>
 	</form>
 </div>
 <?php
diff --git a/src/wp-admin/includes/template.php b/src/wp-admin/includes/template.php
index 4eac951829..f9f463b62f 100644
--- a/src/wp-admin/includes/template.php
+++ b/src/wp-admin/includes/template.php
@@ -423,11 +423,11 @@ function wp_comment_reply( $position = 1, $checkbox = false, $mode = 'single', $
 	</div>
 
 	<p id="replysubmit" class="submit">
-	<a href="#comments-form" class="save button-primary alignright">
+	<a href="#comments-form" class="save button button-primary alignright">
 	<span id="addbtn" style="display:none;"><?php _e('Add Comment'); ?></span>
 	<span id="savebtn" style="display:none;"><?php _e('Update Comment'); ?></span>
 	<span id="replybtn" style="display:none;"><?php _e('Submit Reply'); ?></span></a>
-	<a href="#comments-form" class="cancel button-secondary alignleft"><?php _e('Cancel'); ?></a>
+	<a href="#comments-form" class="cancel button alignleft"><?php _e('Cancel'); ?></a>
 	<span class="waiting spinner"></span>
 	<span class="error" style="display:none;"></span>
 	</p>
@@ -657,7 +657,7 @@ function meta_form( $post = null ) {
 
 <tr><td colspan="2">
 <div class="submit">
-<?php submit_button( __( 'Add Custom Field' ), 'secondary', 'addmeta', false, array( 'id' => 'newmeta-submit', 'data-wp-lists' => 'add:the-list:newmeta' ) ); ?>
+<?php submit_button( __( 'Add Custom Field' ), '', 'addmeta', false, array( 'id' => 'newmeta-submit', 'data-wp-lists' => 'add:the-list:newmeta' ) ); ?>
 </div>
 <?php wp_nonce_field( 'add-meta', '_ajax_nonce-add-meta', false ); ?>
 </td></tr>
@@ -1513,7 +1513,7 @@ function find_posts_div($found_action = '') {
 			<div id="find-posts-response"></div>
 		</div>
 		<div class="find-box-buttons">
-			<?php submit_button( __( 'Select' ), 'button-primary alignright', 'find-posts-submit', false ); ?>
+			<?php submit_button( __( 'Select' ), 'primary alignright', 'find-posts-submit', false ); ?>
 			<div class="clear"></div>
 		</div>
 	</div>
@@ -1914,10 +1914,11 @@ function get_submit_button( $text = '', $type = 'primary large', $name = 'submit
 			continue;
 		$classes[] = in_array( $t, $button_shorthand ) ? 'button-' . $t : $t;
 	}
-	$class = implode( ' ', array_unique( $classes ) );
+	// Remove empty items, remove duplicate items, and finally build a string.
+	$class = implode( ' ', array_unique( array_filter( $classes ) ) );
 
 	if ( 'delete' === $type )
-		$class = 'button-secondary delete';
+		$class = 'button delete';
 
 	$text = $text ? $text : __( 'Save Changes' );
 
diff --git a/src/wp-admin/includes/theme-install.php b/src/wp-admin/includes/theme-install.php
index 9333beac9b..31ce5f7971 100644
--- a/src/wp-admin/includes/theme-install.php
+++ b/src/wp-admin/includes/theme-install.php
@@ -85,7 +85,7 @@ function install_theme_search_form( $type_selector = true ) {
 	<label class="screen-reader-text" for="s"><?php _e('Search by keyword'); ?></label>
 	<?php endif; ?>
 	<input type="search" name="s" id="s" size="30" value="<?php echo esc_attr($term) ?>" autofocus="autofocus" />
-	<?php submit_button( __( 'Search' ), 'button', 'search', false ); ?>
+	<?php submit_button( __( 'Search' ), '', 'search', false ); ?>
 </form>
 <?php
 }
@@ -130,7 +130,7 @@ function install_themes_dashboard() {
 
 </div>
 <br class="clear" />
-<?php submit_button( __( 'Find Themes' ), 'button', 'search' ); ?>
+<?php submit_button( __( 'Find Themes' ), '', 'search' ); ?>
 </form>
 <?php
 }
@@ -145,7 +145,7 @@ function install_themes_upload() {
 	<?php wp_nonce_field( 'theme-upload' ); ?>
 	<label class="screen-reader-text" for="themezip"><?php _e( 'Theme zip file' ); ?></label>
 	<input type="file" id="themezip" name="themezip" />
-	<?php submit_button( __( 'Install Now' ), 'button', 'install-theme-submit', false ); ?>
+	<?php submit_button( __( 'Install Now' ), '', 'install-theme-submit', false ); ?>
 </form>
 	<?php
 }
diff --git a/src/wp-admin/includes/widgets.php b/src/wp-admin/includes/widgets.php
index 746a892798..fe2a957fa7 100644
--- a/src/wp-admin/includes/widgets.php
+++ b/src/wp-admin/includes/widgets.php
@@ -254,7 +254,7 @@ function wp_widget_control( $sidebar_args ) {
 		<a class="widget-control-close" href="#close"><?php _e('Close'); ?></a>
 		</div>
 		<div class="alignright<?php if ( 'noform' === $has_form ) echo ' widget-control-noform'; ?>">
-			<?php submit_button( __( 'Save' ), 'button-primary widget-control-save right', 'savewidget', false, array( 'id' => 'widget-' . esc_attr( $id_format ) . '-savewidget' ) ); ?>
+			<?php submit_button( __( 'Save' ), 'primary widget-control-save right', 'savewidget', false, array( 'id' => 'widget-' . esc_attr( $id_format ) . '-savewidget' ) ); ?>
 			<span class="spinner"></span>
 		</div>
 		<br class="clear" />
@@ -278,4 +278,4 @@ function wp_widget_control( $sidebar_args ) {
  */
 function wp_widgets_access_body_class($classes) {
 	return "$classes widgets_access ";
-}
\ No newline at end of file
+}
diff --git a/src/wp-admin/install.php b/src/wp-admin/install.php
index 80b7fbf1f5..d22ff6ca86 100644
--- a/src/wp-admin/install.php
+++ b/src/wp-admin/install.php
@@ -141,7 +141,7 @@ function display_setup_form( $error = null ) {
 				<div class="">
 					<?php $initial_password = isset( $_POST['admin_password'] ) ? stripslashes( $_POST['admin_password'] ) : wp_generate_password( 18 ); ?>
 					<input type="password" name="admin_password" id="pass1" class="regular-text" autocomplete="off" data-reveal="1" data-pw="<?php echo esc_attr( $initial_password ); ?>" aria-describedby="pass-strength-result" />
-					<button type="button" class="button button-secondary wp-hide-pw hide-if-no-js" data-start-masked="<?php echo (int) isset( $_POST['admin_password'] ); ?>" data-toggle="0" aria-label="<?php esc_attr_e( 'Hide password' ); ?>">
+					<button type="button" class="button wp-hide-pw hide-if-no-js" data-start-masked="<?php echo (int) isset( $_POST['admin_password'] ); ?>" data-toggle="0" aria-label="<?php esc_attr_e( 'Hide password' ); ?>">
 						<span class="dashicons dashicons-hidden"></span>
 						<span class="text"><?php _e( 'Hide' ); ?></span>
 					</button>
diff --git a/src/wp-admin/js/customize-widgets.js b/src/wp-admin/js/customize-widgets.js
index dc1ef823b3..5c956d7e78 100644
--- a/src/wp-admin/js/customize-widgets.js
+++ b/src/wp-admin/js/customize-widgets.js
@@ -835,7 +835,7 @@
 			$saveBtn = this.container.find( '.widget-control-save' );
 			$saveBtn.val( l10n.saveBtnLabel );
 			$saveBtn.attr( 'title', l10n.saveBtnTooltip );
-			$saveBtn.removeClass( 'button-primary' ).addClass( 'button-secondary' );
+			$saveBtn.removeClass( 'button-primary' );
 			$saveBtn.on( 'click', function( e ) {
 				e.preventDefault();
 				self.updateWidget( { disable_form: true } ); // @todo disable_form is unused?
diff --git a/src/wp-admin/js/updates.js b/src/wp-admin/js/updates.js
index 239829fe32..6c5907dfac 100644
--- a/src/wp-admin/js/updates.js
+++ b/src/wp-admin/js/updates.js
@@ -1105,7 +1105,7 @@
 				$message.siblings( '.preview' ).replaceWith( function () {
 					return $( '<a>' )
 						.attr( 'href', response.customizeUrl )
-						.addClass( 'button button-secondary load-customize' )
+						.addClass( 'button load-customize' )
 						.text( wp.updates.l10n.livePreview );
 				} );
 			}
diff --git a/src/wp-admin/js/widgets.js b/src/wp-admin/js/widgets.js
index de64533bdf..aa439ea552 100644
--- a/src/wp-admin/js/widgets.js
+++ b/src/wp-admin/js/widgets.js
@@ -354,12 +354,12 @@ wpWidgets = {
 			if ( $target.hasClass('button-primary') ) {
 				self.addWidget( chooser );
 				self.closeChooser();
-			} else if ( $target.hasClass('button-secondary') ) {
+			} else if ( $target.hasClass( 'widgets-chooser-cancel' ) ) {
 				self.closeChooser();
 			}
 		}).on( 'keyup.widgets-chooser', function( event ) {
 			if ( event.which === $.ui.keyCode.ENTER ) {
-				if ( $( event.target ).hasClass('button-secondary') ) {
+				if ( $( event.target ).hasClass( 'widgets-chooser-cancel' ) ) {
 					// Close instead of adding when pressing Enter on the Cancel button
 					self.closeChooser();
 				} else {
diff --git a/src/wp-admin/nav-menus.php b/src/wp-admin/nav-menus.php
index 4c383e8dc4..319566c424 100644
--- a/src/wp-admin/nav-menus.php
+++ b/src/wp-admin/nav-menus.php
@@ -713,7 +713,7 @@ require_once( ABSPATH . 'wp-admin/admin-header.php' );
 					</option>
 				<?php endforeach; ?>
 			</select>
-			<span class="submit-btn"><input type="submit" class="button-secondary" value="<?php esc_attr_e( 'Select' ); ?>"></span>
+			<span class="submit-btn"><input type="submit" class="button" value="<?php esc_attr_e( 'Select' ); ?>"></span>
 			<span class="add-new-menu-action">
 				<?php printf( __( 'or <a href="%s">create a new menu</a>.' ), esc_url( add_query_arg( array( 'action' => 'edit', 'menu' => 0 ), admin_url( 'nav-menus.php' ) ) ) ); ?>
 			</span><!-- /add-new-menu-action -->
diff --git a/src/wp-admin/network/themes.php b/src/wp-admin/network/themes.php
index 68b7c77ed3..d6e4e95290 100644
--- a/src/wp-admin/network/themes.php
+++ b/src/wp-admin/network/themes.php
@@ -158,9 +158,9 @@ if ( $action ) {
 						wp_nonce_field( 'bulk-themes' );
 
 						if ( 1 == $themes_to_delete ) {
-							submit_button( __( 'Yes, delete this theme' ), 'button', 'submit', false );
+							submit_button( __( 'Yes, delete this theme' ), '', 'submit', false );
 						} else {
-							submit_button( __( 'Yes, delete these themes' ), 'button', 'submit', false );
+							submit_button( __( 'Yes, delete these themes' ), '', 'submit', false );
 						}
 					?>
 				</form>
@@ -168,7 +168,7 @@ if ( $action ) {
 				$referer = wp_get_referer();
 				?>
 				<form method="post" action="<?php echo $referer ? esc_url( $referer ) : ''; ?>" style="display:inline;">
-					<?php submit_button( __( 'No, return me to the theme list' ), 'button', 'submit', false ); ?>
+					<?php submit_button( __( 'No, return me to the theme list' ), '', 'submit', false ); ?>
 				</form>
 			</div>
 				<?php
diff --git a/src/wp-admin/plugin-editor.php b/src/wp-admin/plugin-editor.php
index 9919005416..a5dd63dba1 100644
--- a/src/wp-admin/plugin-editor.php
+++ b/src/wp-admin/plugin-editor.php
@@ -224,7 +224,7 @@ default:
 	}
 ?>
 		</select>
-		<?php submit_button( __( 'Select' ), 'button', 'Submit', false ); ?>
+		<?php submit_button( __( 'Select' ), '', 'Submit', false ); ?>
 	</form>
 </div>
 <br class="clear" />
diff --git a/src/wp-admin/plugins.php b/src/wp-admin/plugins.php
index 6474e4691f..2ea6b372b3 100644
--- a/src/wp-admin/plugins.php
+++ b/src/wp-admin/plugins.php
@@ -327,13 +327,13 @@ if ( $action ) {
 						}
 					?>
 					<?php wp_nonce_field('bulk-plugins') ?>
-					<?php submit_button( $data_to_delete ? __( 'Yes, delete these files and data' ) : __( 'Yes, delete these files' ), 'button', 'submit', false ); ?>
+					<?php submit_button( $data_to_delete ? __( 'Yes, delete these files and data' ) : __( 'Yes, delete these files' ), '', 'submit', false ); ?>
 				</form>
 				<?php
 				$referer = wp_get_referer();
 				?>
 				<form method="post" action="<?php echo $referer ? esc_url( $referer ) : ''; ?>" style="display:inline;">
-					<?php submit_button( __( 'No, return me to the plugin list' ), 'button', 'submit', false ); ?>
+					<?php submit_button( __( 'No, return me to the plugin list' ), '', 'submit', false ); ?>
 				</form>
 			</div>
 				<?php
diff --git a/src/wp-admin/theme-editor.php b/src/wp-admin/theme-editor.php
index 0b100cf881..cd9f8392f1 100644
--- a/src/wp-admin/theme-editor.php
+++ b/src/wp-admin/theme-editor.php
@@ -182,7 +182,7 @@ foreach ( wp_get_themes( array( 'errors' => null ) ) as $a_stylesheet => $a_them
 }
 ?>
 		</select>
-		<?php submit_button( __( 'Select' ), 'button', 'Submit', false ); ?>
+		<?php submit_button( __( 'Select' ), '', 'Submit', false ); ?>
 	</form>
 </div>
 <br class="clear" />
diff --git a/src/wp-admin/theme-install.php b/src/wp-admin/theme-install.php
index fc0904c6d2..87163b925f 100644
--- a/src/wp-admin/theme-install.php
+++ b/src/wp-admin/theme-install.php
@@ -174,7 +174,7 @@ include(ABSPATH . 'wp-admin/admin-header.php');
 				<label for="wporg-username-input"><?php _e( 'Your WordPress.org username:' ); ?></label>
 				<input type="hidden" id="wporg-username-nonce" name="_wpnonce" value="<?php echo esc_attr( wp_create_nonce( $action ) ); ?>" />
 				<input type="search" id="wporg-username-input" value="<?php echo esc_attr( $user ); ?>" />
-				<input type="button" class="button button-secondary favorites-form-submit" value="<?php esc_attr_e( 'Get Favorites' ); ?>" />
+				<input type="button" class="button favorites-form-submit" value="<?php esc_attr_e( 'Get Favorites' ); ?>" />
 			</p>
 		</div>
 
@@ -262,9 +262,9 @@ if ( $tab ) {
 				<a class="button button-primary activate" href="{{ data.activate_url }}" aria-label="<?php echo esc_attr( $aria_label ); ?>"><?php _e( 'Activate' ); ?></a>
 			<# } #>
 			<# if ( data.customize_url ) { #>
-				<a class="button button-secondary load-customize" href="{{ data.customize_url }}"><?php _e( 'Live Preview' ); ?></a>
+				<a class="button load-customize" href="{{ data.customize_url }}"><?php _e( 'Live Preview' ); ?></a>
 			<# } else { #>
-				<button class="button-secondary preview install-theme-preview"><?php _e( 'Preview' ); ?></button>
+				<button class="button preview install-theme-preview"><?php _e( 'Preview' ); ?></button>
 			<# } #>
 		<# } else { #>
 			<?php
@@ -272,7 +272,7 @@ if ( $tab ) {
 			$aria_label = sprintf( __( 'Install %s' ), '{{ data.name }}' );
 			?>
 			<a class="button button-primary theme-install" data-name="{{ data.name }}" data-slug="{{ data.id }}" href="{{ data.install_url }}" aria-label="<?php echo esc_attr( $aria_label ); ?>"><?php _e( 'Install' ); ?></a>
-			<button class="button-secondary preview install-theme-preview"><?php _e( 'Preview' ); ?></button>
+			<button class="button preview install-theme-preview"><?php _e( 'Preview' ); ?></button>
 		<# } #>
 	</div>
 
@@ -325,7 +325,7 @@ if ( $tab ) {
 				</div>
 			</div>
 			<div class="wp-full-overlay-footer">
-				<button type="button" class="collapse-sidebar button-secondary" aria-expanded="true" aria-label="<?php esc_attr_e( 'Collapse Sidebar' ); ?>">
+				<button type="button" class="collapse-sidebar button" aria-expanded="true" aria-label="<?php esc_attr_e( 'Collapse Sidebar' ); ?>">
 					<span class="collapse-sidebar-arrow"></span>
 					<span class="collapse-sidebar-label"><?php _e( 'Collapse' ); ?></span>
 				</button>
diff --git a/src/wp-admin/themes.php b/src/wp-admin/themes.php
index d480ce672b..6c455c079c 100644
--- a/src/wp-admin/themes.php
+++ b/src/wp-admin/themes.php
@@ -200,17 +200,17 @@ if ( ! $ct->errors() || ( 1 == count( $ct->errors()->get_error_codes() )
 				$submenu[$item[2]] = array_values($submenu[$item[2]]); // Re-index.
 				$menu_hook = get_plugin_page_hook($submenu[$item[2]][0][2], $item[2]);
 				if ( file_exists(WP_PLUGIN_DIR . "/{$submenu[$item[2]][0][2]}") || !empty($menu_hook))
-					$current_theme_actions[] = "<a class='button button-secondary$class' href='admin.php?page={$submenu[$item[2]][0][2]}'>{$item[0]}</a>";
+					$current_theme_actions[] = "<a class='button$class' href='admin.php?page={$submenu[$item[2]][0][2]}'>{$item[0]}</a>";
 				else
-					$current_theme_actions[] = "<a class='button button-secondary$class' href='{$submenu[$item[2]][0][2]}'>{$item[0]}</a>";
+					$current_theme_actions[] = "<a class='button$class' href='{$submenu[$item[2]][0][2]}'>{$item[0]}</a>";
 			} elseif ( ! empty( $item[2] ) && current_user_can( $item[1] ) ) {
 				$menu_file = $item[2];
 
 				if ( current_user_can( 'customize' ) ) {
 					if ( 'custom-header' === $menu_file ) {
-						$current_theme_actions[] = "<a class='button button-secondary hide-if-no-customize$class' href='customize.php?autofocus[control]=header_image'>{$item[0]}</a>";
+						$current_theme_actions[] = "<a class='button hide-if-no-customize$class' href='customize.php?autofocus[control]=header_image'>{$item[0]}</a>";
 					} elseif ( 'custom-background' === $menu_file ) {
-						$current_theme_actions[] = "<a class='button button-secondary hide-if-no-customize$class' href='customize.php?autofocus[control]=background_image'>{$item[0]}</a>";
+						$current_theme_actions[] = "<a class='button hide-if-no-customize$class' href='customize.php?autofocus[control]=background_image'>{$item[0]}</a>";
 					}
 				}
 
@@ -219,9 +219,9 @@ if ( ! $ct->errors() || ( 1 == count( $ct->errors()->get_error_codes() )
 				}
 
 				if ( file_exists( ABSPATH . "wp-admin/$menu_file" ) ) {
-					$current_theme_actions[] = "<a class='button button-secondary$class' href='{$item[2]}'>{$item[0]}</a>";
+					$current_theme_actions[] = "<a class='button$class' href='{$item[2]}'>{$item[0]}</a>";
 				} else {
-					$current_theme_actions[] = "<a class='button button-secondary$class' href='themes.php?page={$item[2]}'>{$item[0]}</a>";
+					$current_theme_actions[] = "<a class='button$class' href='themes.php?page={$item[2]}'>{$item[0]}</a>";
 				}
 			}
 		}
@@ -281,7 +281,7 @@ foreach ( $themes as $theme ) :
 		/* translators: %s: Theme name */
 		$aria_label = sprintf( _x( 'Activate %s', 'theme' ), '{{ data.name }}' );
 		?>
-		<a class="button button-secondary activate" href="<?php echo $theme['actions']['activate']; ?>" aria-label="<?php echo esc_attr( $aria_label ); ?>"><?php _e( 'Activate' ); ?></a>
+		<a class="button activate" href="<?php echo $theme['actions']['activate']; ?>" aria-label="<?php echo esc_attr( $aria_label ); ?>"><?php _e( 'Activate' ); ?></a>
 		<?php if ( current_user_can( 'edit_theme_options' ) && current_user_can( 'customize' ) ) { ?>
 			<a class="button button-primary load-customize hide-if-no-customize" href="<?php echo $theme['actions']['customize']; ?>"><?php _e( 'Live Preview' ); ?></a>
 		<?php } ?>
@@ -333,7 +333,7 @@ $can_install = current_user_can( 'install_themes' );
 				), admin_url( 'themes.php' ) );
 				$delete_url = wp_nonce_url( $delete_url, 'delete-theme_' . $stylesheet );
 				?>
-				<td><a href="<?php echo esc_url( $delete_url ); ?>" class="button button-secondary delete-theme"><?php _e( 'Delete' ); ?></a></td>
+				<td><a href="<?php echo esc_url( $delete_url ); ?>" class="button delete-theme"><?php _e( 'Delete' ); ?></a></td>
 				<?php
 			}
 
@@ -348,7 +348,7 @@ $can_install = current_user_can( 'install_themes' );
 					), admin_url( 'update.php' ) );
 					$install_url = wp_nonce_url( $install_url, 'install-theme_' . $parent_theme_name );
 					?>
-					<td><a href="<?php echo esc_url( $install_url ); ?>" class="button button-secondary install-theme"><?php _e( 'Install Parent Theme' ); ?></a></td>
+					<td><a href="<?php echo esc_url( $install_url ); ?>" class="button install-theme"><?php _e( 'Install Parent Theme' ); ?></a></td>
 					<?php
 				}
 			}
@@ -410,7 +410,7 @@ $can_install = current_user_can( 'install_themes' );
 			/* translators: %s: Theme name */
 			$aria_label = sprintf( _x( 'Activate %s', 'theme' ), '{{ data.name }}' );
 			?>
-			<a class="button button-secondary activate" href="{{{ data.actions.activate }}}" aria-label="<?php echo $aria_label; ?>"><?php _e( 'Activate' ); ?></a>
+			<a class="button activate" href="{{{ data.actions.activate }}}" aria-label="<?php echo $aria_label; ?>"><?php _e( 'Activate' ); ?></a>
 			<a class="button button-primary load-customize hide-if-no-customize" href="{{{ data.actions.customize }}}"><?php _e( 'Live Preview' ); ?></a>
 		<# } #>
 	</div>
@@ -469,13 +469,13 @@ $can_install = current_user_can( 'install_themes' );
 				$aria_label = sprintf( _x( 'Activate %s', 'theme' ), '{{ data.name }}' );
 				?>
 				<# if ( data.actions.activate ) { #>
-					<a href="{{{ data.actions.activate }}}" class="button button-secondary activate" aria-label="<?php echo $aria_label; ?>"><?php _e( 'Activate' ); ?></a>
+					<a href="{{{ data.actions.activate }}}" class="button activate" aria-label="<?php echo $aria_label; ?>"><?php _e( 'Activate' ); ?></a>
 				<# } #>
 				<a href="{{{ data.actions.customize }}}" class="button button-primary load-customize hide-if-no-customize"><?php _e( 'Live Preview' ); ?></a>
 			</div>
 
 			<# if ( ! data.active && data.actions['delete'] ) { #>
-				<a href="{{{ data.actions['delete'] }}}" class="button button-secondary delete-theme"><?php _e( 'Delete' ); ?></a>
+				<a href="{{{ data.actions['delete'] }}}" class="button delete-theme"><?php _e( 'Delete' ); ?></a>
 			<# } #>
 		</div>
 	</div>
diff --git a/src/wp-admin/tools.php b/src/wp-admin/tools.php
index b6de3c8183..3ca351be35 100644
--- a/src/wp-admin/tools.php
+++ b/src/wp-admin/tools.php
@@ -49,7 +49,7 @@ require_once( ABSPATH . 'wp-admin/admin-header.php' );
 
 		<p class="pressthis-bookmarklet-wrapper">
 			<a class="pressthis-bookmarklet" onclick="return false;" href="<?php echo htmlspecialchars( get_shortcut_link() ); ?>"><span><?php _e( 'Press This' ); ?></span></a>
-			<button type="button" class="button button-secondary pressthis-js-toggle js-show-pressthis-code-wrap" aria-expanded="false" aria-controls="pressthis-code-wrap">
+			<button type="button" class="button pressthis-js-toggle js-show-pressthis-code-wrap" aria-expanded="false" aria-controls="pressthis-code-wrap">
 				<span class="dashicons dashicons-clipboard"></span>
 				<span class="screen-reader-text"><?php _e( 'Copy &#8220;Press This&#8221; bookmarklet code' ) ?></span>
 			</button>
@@ -68,7 +68,7 @@ require_once( ABSPATH . 'wp-admin/admin-header.php' );
 		<p><?php _e( 'Follow the link to open Press This. Then add it to your device&#8217;s bookmarks or home screen.' ); ?></p>
 
 		<p>
-			<a class="button button-secondary" href="<?php echo htmlspecialchars( admin_url( 'press-this.php' ) ); ?>"><?php _e( 'Open Press This' ) ?></a>
+			<a class="button" href="<?php echo htmlspecialchars( admin_url( 'press-this.php' ) ); ?>"><?php _e( 'Open Press This' ) ?></a>
 		</p>
 		<script>
 			jQuery( document ).ready( function( $ ) {
diff --git a/src/wp-admin/update-core.php b/src/wp-admin/update-core.php
index cb6136fef2..d203a8b20b 100644
--- a/src/wp-admin/update-core.php
+++ b/src/wp-admin/update-core.php
@@ -92,18 +92,18 @@ function list_core_update( $update ) {
 	echo '<input name="locale" value="'. esc_attr($update->locale) .'" type="hidden"/>';
 	if ( $show_buttons ) {
 		if ( $first_pass ) {
-			submit_button( $submit, $current ? 'button' : 'primary regular', 'upgrade', false );
+			submit_button( $submit, $current ? '' : 'primary regular', 'upgrade', false );
 			$first_pass = false;
 		} else {
-			submit_button( $submit, 'button', 'upgrade', false );
+			submit_button( $submit, '', 'upgrade', false );
 		}
 		echo '&nbsp;<a href="' . esc_url( $update->download ) . '" class="button">' . $download . '</a>&nbsp;';
 	}
 	if ( 'en_US' != $update->locale )
 		if ( !isset( $update->dismissed ) || !$update->dismissed )
-			submit_button( __('Hide this update'), 'button', 'dismiss', false );
+			submit_button( __( 'Hide this update' ), '', 'dismiss', false );
 		else
-			submit_button( __('Bring back this update'), 'button', 'undismiss', false );
+			submit_button( __( 'Bring back this update' ), '', 'undismiss', false );
 	echo '</p>';
 	if ( 'en_US' != $update->locale && ( !isset($wp_local_package) || $wp_local_package != $update->locale ) )
 	    echo '<p class="hint">'.__('This localized version contains both the translation and various other localization fixes. You can skip upgrading if you want to keep your current translation.').'</p>';
diff --git a/src/wp-admin/user-edit.php b/src/wp-admin/user-edit.php
index bb3c62ec97..b97cdddd95 100644
--- a/src/wp-admin/user-edit.php
+++ b/src/wp-admin/user-edit.php
@@ -505,16 +505,16 @@ if ( $show_password_fields = apply_filters( 'show_password_fields', true, $profi
 	<th><label for="pass1"><?php _e( 'New Password' ); ?></label></th>
 	<td>
 		<input class="hidden" value=" " /><!-- #24364 workaround -->
-		<button type="button" class="button button-secondary wp-generate-pw hide-if-no-js"><?php _e( 'Generate Password' ); ?></button>
+		<button type="button" class="button wp-generate-pw hide-if-no-js"><?php _e( 'Generate Password' ); ?></button>
 		<div class="wp-pwd hide-if-js">
 			<span class="password-input-wrapper">
 				<input type="password" name="pass1" id="pass1" class="regular-text" value="" autocomplete="off" data-pw="<?php echo esc_attr( wp_generate_password( 24 ) ); ?>" aria-describedby="pass-strength-result" />
 			</span>
-			<button type="button" class="button button-secondary wp-hide-pw hide-if-no-js" data-toggle="0" aria-label="<?php esc_attr_e( 'Hide password' ); ?>">
+			<button type="button" class="button wp-hide-pw hide-if-no-js" data-toggle="0" aria-label="<?php esc_attr_e( 'Hide password' ); ?>">
 				<span class="dashicons dashicons-hidden"></span>
 				<span class="text"><?php _e( 'Hide' ); ?></span>
 			</button>
-			<button type="button" class="button button-secondary wp-cancel-pw hide-if-no-js" data-toggle="0" aria-label="<?php esc_attr_e( 'Cancel password change' ); ?>">
+			<button type="button" class="button wp-cancel-pw hide-if-no-js" data-toggle="0" aria-label="<?php esc_attr_e( 'Cancel password change' ); ?>">
 				<span class="text"><?php _e( 'Cancel' ); ?></span>
 			</button>
 			<div style="display:none" id="pass-strength-result" aria-live="polite"></div>
@@ -544,7 +544,7 @@ if ( IS_PROFILE_PAGE && count( $sessions->get_all() ) === 1 ) : ?>
 	<tr class="user-sessions-wrap hide-if-no-js">
 		<th><?php _e( 'Sessions' ); ?></th>
 		<td aria-live="assertive">
-			<div class="destroy-sessions"><button type="button" disabled class="button button-secondary"><?php _e( 'Log Out Everywhere Else' ); ?></button></div>
+			<div class="destroy-sessions"><button type="button" disabled class="button"><?php _e( 'Log Out Everywhere Else' ); ?></button></div>
 			<p class="description">
 				<?php _e( 'You are only logged in at this location.' ); ?>
 			</p>
@@ -554,7 +554,7 @@ if ( IS_PROFILE_PAGE && count( $sessions->get_all() ) === 1 ) : ?>
 	<tr class="user-sessions-wrap hide-if-no-js">
 		<th><?php _e( 'Sessions' ); ?></th>
 		<td aria-live="assertive">
-			<div class="destroy-sessions"><button type="button" class="button button-secondary" id="destroy-sessions"><?php _e( 'Log Out Everywhere Else' ); ?></button></div>
+			<div class="destroy-sessions"><button type="button" class="button" id="destroy-sessions"><?php _e( 'Log Out Everywhere Else' ); ?></button></div>
 			<p class="description">
 				<?php _e( 'Did you lose your phone or leave your account logged in at a public computer? You can log out everywhere else, and stay logged in here.' ); ?>
 			</p>
@@ -564,7 +564,7 @@ if ( IS_PROFILE_PAGE && count( $sessions->get_all() ) === 1 ) : ?>
 	<tr class="user-sessions-wrap hide-if-no-js">
 		<th><?php _e( 'Sessions' ); ?></th>
 		<td>
-			<p><button type="button" class="button button-secondary" id="destroy-sessions"><?php _e( 'Log Out Everywhere' ); ?></button></p>
+			<p><button type="button" class="button" id="destroy-sessions"><?php _e( 'Log Out Everywhere' ); ?></button></p>
 			<p class="description">
 				<?php
 				/* translators: 1: User's display name. */
diff --git a/src/wp-admin/user-new.php b/src/wp-admin/user-new.php
index bdd992122d..10cbdd3a49 100644
--- a/src/wp-admin/user-new.php
+++ b/src/wp-admin/user-new.php
@@ -421,17 +421,17 @@ $new_user_ignore_pass = $creating && isset( $_POST['noconfirmation'] ) ? wp_unsl
 		</th>
 		<td>
 			<input class="hidden" value=" " /><!-- #24364 workaround -->
-			<button type="button" class="button button-secondary wp-generate-pw hide-if-no-js"><?php _e( 'Show password' ); ?></button>
+			<button type="button" class="button wp-generate-pw hide-if-no-js"><?php _e( 'Show password' ); ?></button>
 			<div class="wp-pwd hide-if-js">
 				<?php $initial_password = wp_generate_password( 24 ); ?>
 				<span class="password-input-wrapper">
 					<input type="password" name="pass1" id="pass1" class="regular-text" autocomplete="off" data-reveal="1" data-pw="<?php echo esc_attr( $initial_password ); ?>" aria-describedby="pass-strength-result" />
 				</span>
-				<button type="button" class="button button-secondary wp-hide-pw hide-if-no-js" data-toggle="0" aria-label="<?php esc_attr_e( 'Hide password' ); ?>">
+				<button type="button" class="button wp-hide-pw hide-if-no-js" data-toggle="0" aria-label="<?php esc_attr_e( 'Hide password' ); ?>">
 					<span class="dashicons dashicons-hidden"></span>
 					<span class="text"><?php _e( 'Hide' ); ?></span>
 				</button>
-				<button type="button" class="button button-secondary wp-cancel-pw hide-if-no-js" data-toggle="0" aria-label="<?php esc_attr_e( 'Cancel password change' ); ?>">
+				<button type="button" class="button wp-cancel-pw hide-if-no-js" data-toggle="0" aria-label="<?php esc_attr_e( 'Cancel password change' ); ?>">
 					<span class="text"><?php _e( 'Cancel' ); ?></span>
 				</button>
 				<div style="display:none" id="pass-strength-result" aria-live="polite"></div>
diff --git a/src/wp-admin/widgets.php b/src/wp-admin/widgets.php
index a9876b891c..6919a5d632 100644
--- a/src/wp-admin/widgets.php
+++ b/src/wp-admin/widgets.php
@@ -315,9 +315,9 @@ if ( isset($_GET['editwidget']) && $_GET['editwidget'] ) {
 	<a href="widgets.php" class="button alignleft"><?php _e('Cancel'); ?></a>
 <?php
 	} else {
-		submit_button( __( 'Delete' ), 'button alignleft', 'removewidget', false );
+		submit_button( __( 'Delete' ), 'alignleft', 'removewidget', false );
 	}
-	submit_button( __( 'Save Widget' ), 'button-primary alignright', 'savewidget', false ); ?>
+	submit_button( __( 'Save Widget' ), 'primary alignright', 'savewidget', false ); ?>
 	<input type="hidden" name="widget-id" class="widget-id" value="<?php echo esc_attr($widget_id); ?>" />
 	<input type="hidden" name="id_base" class="id_base" value="<?php echo esc_attr($id_base); ?>" />
 	<input type="hidden" name="multi_number" class="multi_number" value="<?php echo esc_attr($multi_number); ?>" />
@@ -500,8 +500,8 @@ foreach ( $theme_sidebars as $sidebar => $registered_sidebar ) {
 <div class="widgets-chooser">
 	<ul class="widgets-chooser-sidebars"></ul>
 	<div class="widgets-chooser-actions">
-		<button class="button-secondary"><?php _e( 'Cancel' ); ?></button>
-		<button class="button-primary"><?php _e( 'Add Widget' ); ?></button>
+		<button class="button widgets-chooser-cancel"><?php _e( 'Cancel' ); ?></button>
+		<button class="button button-primary widgets-chooser-add"><?php _e( 'Add Widget' ); ?></button>
 	</div>
 </div>
 
diff --git a/src/wp-includes/class-wp-customize-nav-menus.php b/src/wp-includes/class-wp-customize-nav-menus.php
index 87dcadb7c1..2487ab05f1 100644
--- a/src/wp-includes/class-wp-customize-nav-menus.php
+++ b/src/wp-includes/class-wp-customize-nav-menus.php
@@ -914,7 +914,7 @@ final class WP_Customize_Nav_Menus {
 					</p>
 					<p class="button-controls">
 						<span class="add-to-menu">
-							<input type="submit" class="button-secondary submit-add-to-menu right" value="<?php esc_attr_e( 'Add to Menu' ); ?>" name="add-custom-menu-item" id="custom-menu-item-submit">
+							<input type="submit" class="button submit-add-to-menu right" value="<?php esc_attr_e( 'Add to Menu' ); ?>" name="add-custom-menu-item" id="custom-menu-item-submit">
 							<span class="spinner"></span>
 						</span>
 					</p>
diff --git a/src/wp-includes/class-wp-customize-widgets.php b/src/wp-includes/class-wp-customize-widgets.php
index 16549ff692..7db6631eb6 100644
--- a/src/wp-includes/class-wp-customize-widgets.php
+++ b/src/wp-includes/class-wp-customize-widgets.php
@@ -712,7 +712,7 @@ final class WP_Customize_Widgets {
 					<% }); %>
 				</ul>
 				<div class="move-widget-actions">
-					<button class="move-widget-btn button-secondary" type="button">{btn}</button>
+					<button class="move-widget-btn button" type="button">{btn}</button>
 				</div>
 			</div>'
 		);
diff --git a/src/wp-includes/customize/class-wp-customize-nav-menu-control.php b/src/wp-includes/customize/class-wp-customize-nav-menu-control.php
index 7dfd187218..64292a73e7 100644
--- a/src/wp-includes/customize/class-wp-customize-nav-menu-control.php
+++ b/src/wp-includes/customize/class-wp-customize-nav-menu-control.php
@@ -48,7 +48,7 @@ class WP_Customize_Nav_Menu_Control extends WP_Customize_Control {
 	 */
 	public function content_template() {
 		?>
-		<button type="button" class="button-secondary add-new-menu-item" aria-label="<?php esc_attr_e( 'Add or remove menu items' ); ?>" aria-expanded="false" aria-controls="available-menu-items">
+		<button type="button" class="button add-new-menu-item" aria-label="<?php esc_attr_e( 'Add or remove menu items' ); ?>" aria-expanded="false" aria-controls="available-menu-items">
 			<?php _e( 'Add Items' ); ?>
 		</button>
 		<button type="button" class="button-link reorder-toggle" aria-label="<?php esc_attr_e( 'Reorder menu items' ); ?>" aria-describedby="reorder-items-desc-{{ data.menu_id }}">
diff --git a/src/wp-includes/customize/class-wp-customize-new-menu-section.php b/src/wp-includes/customize/class-wp-customize-new-menu-section.php
index 0495264a0d..ba75928f88 100644
--- a/src/wp-includes/customize/class-wp-customize-new-menu-section.php
+++ b/src/wp-includes/customize/class-wp-customize-new-menu-section.php
@@ -36,7 +36,7 @@ class WP_Customize_New_Menu_Section extends WP_Customize_Section {
 	protected function render() {
 		?>
 		<li id="accordion-section-<?php echo esc_attr( $this->id ); ?>" class="accordion-section-new-menu">
-			<button type="button" class="button-secondary add-new-menu-item add-menu-toggle" aria-expanded="false">
+			<button type="button" class="button add-new-menu-item add-menu-toggle" aria-expanded="false">
 				<?php echo esc_html( $this->title ); ?>
 			</button>
 			<ul class="new-menu-section-content"></ul>
diff --git a/src/wp-includes/customize/class-wp-widget-area-customize-control.php b/src/wp-includes/customize/class-wp-widget-area-customize-control.php
index 298aece9b3..8f76169c9e 100644
--- a/src/wp-includes/customize/class-wp-widget-area-customize-control.php
+++ b/src/wp-includes/customize/class-wp-widget-area-customize-control.php
@@ -57,7 +57,7 @@ class WP_Widget_Area_Customize_Control extends WP_Customize_Control {
 	public function render_content() {
 		$id = 'reorder-widgets-desc-' . str_replace( array( '[', ']' ), array( '-', '' ), $this->id );
 		?>
-		<button type="button" class="button-secondary add-new-widget" aria-expanded="false" aria-controls="available-widgets">
+		<button type="button" class="button add-new-widget" aria-expanded="false" aria-controls="available-widgets">
 			<?php _e( 'Add a Widget' ); ?>
 		</button>
 		<button type="button" class="button-link reorder-toggle" aria-label="<?php esc_attr_e( 'Reorder widgets' ); ?>" aria-describedby="<?php echo esc_attr( $id ); ?>">
diff --git a/src/wp-includes/general-template.php b/src/wp-includes/general-template.php
index 488e222b97..cc9178d4a5 100644
--- a/src/wp-includes/general-template.php
+++ b/src/wp-includes/general-template.php
@@ -481,7 +481,7 @@ function wp_login_form( $args = array() ) {
 			' . $login_form_middle . '
 			' . ( $args['remember'] ? '<p class="login-remember"><label><input name="rememberme" type="checkbox" id="' . esc_attr( $args['id_remember'] ) . '" value="forever"' . ( $args['value_remember'] ? ' checked="checked"' : '' ) . ' /> ' . esc_html( $args['label_remember'] ) . '</label></p>' : '' ) . '
 			<p class="login-submit">
-				<input type="submit" name="wp-submit" id="' . esc_attr( $args['id_submit'] ) . '" class="button-primary" value="' . esc_attr( $args['label_log_in'] ) . '" />
+				<input type="submit" name="wp-submit" id="' . esc_attr( $args['id_submit'] ) . '" class="button button-primary" value="' . esc_attr( $args['label_log_in'] ) . '" />
 				<input type="hidden" name="redirect_to" value="' . esc_url( $args['redirect'] ) . '" />
 			</p>
 			' . $login_form_bottom . '
diff --git a/tests/qunit/fixtures/customize-menus.js b/tests/qunit/fixtures/customize-menus.js
index f3ac0a1b0a..0525ac42ff 100644
--- a/tests/qunit/fixtures/customize-menus.js
+++ b/tests/qunit/fixtures/customize-menus.js
@@ -378,7 +378,7 @@ window._wpCustomizeSettings.sections.add_menu = {
 	'panel': 'nav_menus',
 	'type': 'new_menu',
 	'title': 'Add a Menu',
-	'content': '<li id="accordion-section-add_menu" class="accordion-section-new-menu">\n\t\t\t<button type="button" class="button-secondary add-new-menu-item add-menu-toggle" aria-expanded="false">\n\t\t\t\tAdd a Menu\t\t\t<\/button>\n\t\t\t<ul class="new-menu-section-content"><\/ul>\n\t\t<\/li>',
+	'content': '<li id="accordion-section-add_menu" class="accordion-section-new-menu">\n\t\t\t<button type="button" class="button add-new-menu-item add-menu-toggle" aria-expanded="false">\n\t\t\t\tAdd a Menu\t\t\t<\/button>\n\t\t\t<ul class="new-menu-section-content"><\/ul>\n\t\t<\/li>',
 	'active': true,
 	'instanceNumber': 16,
 	'customizeAction': 'Customizing &#9656; Menus'
diff --git a/tests/qunit/fixtures/customize-widgets.js b/tests/qunit/fixtures/customize-widgets.js
index e94fc002db..95ecce8fc6 100644
--- a/tests/qunit/fixtures/customize-widgets.js
+++ b/tests/qunit/fixtures/customize-widgets.js
@@ -56,7 +56,7 @@ window._wpCustomizeWidgetsSettings = {
 	},
 	'tpl': {
 		'widgetReorderNav': '<div class="widget-reorder-nav"><span class="move-widget" tabindex="0">Move to another area&hellip;</span><span class="move-widget-down" tabindex="0">Move down</span><span class="move-widget-up" tabindex="0">Move up</span></div>',
-		'moveWidgetArea': '<div class="move-widget-area"> <p class="description">Select an area to move this widget into:</p> <ul class="widget-area-select"> <% _.each( sidebars, function ( sidebar ){ %> <li class="" data-id="<%- sidebar.id %>" title="<%- sidebar.description %>" tabindex="0"><%- sidebar.name %></li> <% }); %> </ul> <div class="move-widget-actions"> <button class="move-widget-btn button-secondary" type="button">Move</button> </div> </div>'
+		'moveWidgetArea': '<div class="move-widget-area"> <p class="description">Select an area to move this widget into:</p> <ul class="widget-area-select"> <% _.each( sidebars, function ( sidebar ){ %> <li class="" data-id="<%- sidebar.id %>" title="<%- sidebar.description %>" tabindex="0"><%- sidebar.name %></li> <% }); %> </ul> <div class="move-widget-actions"> <button class="move-widget-btn button" type="button">Move</button> </div> </div>'
 	}
 };
 
@@ -130,7 +130,7 @@ window._wpCustomizeSettings.controls['sidebars_widgets[sidebar-1]'] = {
 	'priority': 99,
 	'active': true,
 	'section': 'sidebar-widgets-sidebar-1',
-	'content': '<li id="customize-control-sidebars_widgets-sidebar-1" class="customize-control customize-control-sidebar_widgets"> <span class="button-secondary add-new-widget" tabindex="0">    Add a Widget  <\/span> <span class="reorder-toggle" tabindex="0"> <span class="reorder">Reorder<\/span> <span class="reorder-done">Done<\/span> <\/span> <\/li>',
+	'content': '<li id="customize-control-sidebars_widgets-sidebar-1" class="customize-control customize-control-sidebar_widgets"> <span class="button add-new-widget" tabindex="0">    Add a Widget  <\/span> <span class="reorder-toggle" tabindex="0"> <span class="reorder">Reorder<\/span> <span class="reorder-done">Done<\/span> <\/span> <\/li>',
 	'label': '',
 	'description': '',
 	'instanceNumber': 1,
diff --git a/tests/qunit/index.html b/tests/qunit/index.html
index ff8ae004e4..85a3bd713d 100644
--- a/tests/qunit/index.html
+++ b/tests/qunit/index.html
@@ -144,7 +144,7 @@
 
 		<!-- Templates for Customizer Menus -->
 		<script type="text/html" id="tmpl-customize-control-nav_menu-content">
-					<button type="button" class="button-secondary add-new-menu-item" aria-label="Add or remove menu items" aria-expanded="false" aria-controls="available-menu-items">
+					<button type="button" class="button add-new-menu-item" aria-label="Add or remove menu items" aria-expanded="false" aria-controls="available-menu-items">
 			Add Items		</button>
 		<button type="button" class="not-a-button reorder-toggle" aria-label="Reorder menu items" aria-describedby="reorder-items-desc-{{ data.menu_id }}">
 			<span class="reorder">Reorder</span>
@@ -359,7 +359,7 @@
 					</p>
 					<p class="button-controls">
 						<span class="add-to-menu">
-							<input type="submit" class="button-secondary submit-add-to-menu right" value="Add to Menu" name="add-custom-menu-item" id="custom-menu-item-submit">
+							<input type="submit" class="button submit-add-to-menu right" value="Add to Menu" name="add-custom-menu-item" id="custom-menu-item-submit">
 							<span class="spinner"></span>
 						</span>
 					</p>