customizable menu button

kit/functions.php

@@ -10,13 +10,22 @@ function kit_setup() {
 
   register_nav_menus( array(
     'primary' => 'Main Menu',
-    'secondary' => 'Footer Menu'
+    'secondary' => 'Footer Menu',
+    'extra' => 'Extra Menu'
   ) );
 
 };
 
 add_action( 'after_setup_theme', 'kit_setup' );
 
+function add_menu_link_class( $atts, $item, $args ) {
+  if (property_exists($args, 'link_class')) {
+    $atts['class'] = $args->link_class;
+  }
+  return $atts;
+}
+add_filter( 'nav_menu_link_attributes', 'add_menu_link_class', 1, 3 );
+
 class kit_custom_main_menu extends Walker_Nav_Menu {
 
   function start_lvl( &$output, $depth = 0, $args = array() ) {

kit/header.php

@@ -148,7 +148,20 @@
       <?php get_template_part('template-parts/site-nav'); ?>
 
       <div class="header-button-container">
-        <a href="https://www.kit-ausbildung.de/de/offene-stellen" class="header-button"><span>Zum Bestand</span></a>
+        <?php
+          $menuParameters = array(
+            'container'       => false,
+            'echo'            => false,
+            'items_wrap'      => '%3$s',
+            'depth'           => 0,
+            'theme_location' => 'extra',
+            'link_class'   =>  'header-button',
+            'link_before' => '<span>',
+            'link_after' => '</span>',
+          );
+          echo strip_tags(wp_nav_menu( $menuParameters ), '<span><a>' );
+        ?>
+        <!-- <a href="https://www.kit-ausbildung.de/de/offene-stellen" class="header-button"><span>Zum Bestand</span></a> -->
       </div>
 
     </div>