Theme and nav improvements: lang switcher styling, dropdown, theme thumbnail

- Style language switcher dropdown to match site colours
- Move language switcher left of social icons
- Set theme thumbnail to logo PNG in blueprints
- Add Dutch language override and system config tweaks
- Various CSS fixes for dropdown alignment and width

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

user/themes/natascha/blueprints.yaml

@@ -2,5 +2,6 @@ name: Natascha
 version: 1.0.0
 description: Custom theme for Natascha Rieter art gallery website
 type: theme
+thumbnail: /user/themes/natascha/images/logo-blauw.png
 author:
   name: Claude

user/themes/natascha/css/custom.css

@@ -81,6 +81,27 @@ body {
     box-shadow: 0 0 0 0.25rem rgba(255, 255, 255, 0.25);
 }
 
+#main-menu .nav-item.dropdown .nav-link {
+    line-height: 25px;
+    padding-top: 0;
+    padding-bottom: 0;
+}
+
+#main-menu .dropdown-menu {
+    background-color: #0081c4;
+    border-color: #fff;
+    min-width: 0;
+}
+
+#main-menu .dropdown-menu .dropdown-item {
+    color: #fff;
+}
+
+#main-menu .dropdown-menu .dropdown-item:hover {
+    background-color: #0081c4;
+    color: #293236;
+}
+
 img.social-icon {
     filter: invert(1);
 }

user/themes/natascha/templates/partials/langswitcher.html.twig

@@ -1,7 +1,7 @@
 {% extends 'partials/langswitcher-logic.html.twig' %}
 
 {% block language_block_start %}
-<li class="nav-item dropdown">
+<li class="nav-item dropdown d-flex align-items-center">
     <a class="nav-link dropdown-toggle p-1" href="#" role="button" data-bs-toggle="dropdown" aria-expanded="false">
         {{ langswitcher.current|upper }}
     </a>

user/themes/natascha/templates/partials/nav.html.twig

@@ -17,6 +17,7 @@
                 </li>
                 {% endif %}
                 {% endfor %}
+                {% include 'partials/langswitcher.html.twig' %}
                 <li class="nav-item">
                     <a class="nav-link p-1" href="#" aria-label="Instagram">
                         <img src="{{ url('theme://images/icon-instagram.png') }}" height="25" class="social-icon" alt="Instagram">
@@ -32,7 +33,6 @@
                         <img src="{{ url('theme://images/icon-linked-in.png') }}" height="25" class="social-icon" alt="LinkedIn">
                     </a>
                 </li>
-                {% include 'partials/langswitcher.html.twig' %}
             </ul>
         </div>
     </div>