fix the href.

_includes/header.html

@@ -9,7 +9,7 @@
                 {% if menu_items.first.parent_menu %}
                     {% assign check_url = menu_items.first.parent_menu | downcase | prepend: '/' | append: '/'  %}
                     <li class="dropdown">
-                        <a class="nav-link {% if page.url contains check_url %}active{% endif %} dropbtn" href="#">{{ menu_items.first.parent_menu }}</a>
+                        <a class="nav-link {% if page.url contains check_url %}active{% endif %} dropbtn" href="">{{ menu_items.first.parent_menu }}</a>
                         <div class="dropdown-content">
                         {% for item in menu_items %}
                         <a class="nav-link {% if item.url == page.url %}active{% endif %}" href="{{ item.url | prepend: site.baseurl }}">{{ item.title }}</a>