Remove custom CSS, use class from visually hidden plugin

source/_partials/post/tags.html.twig

@@ -1,5 +1,5 @@
 {% if page.tags %}
-    <h2 class="element-invisible">Tags</h2>
+    <h2 class="visuallyhidden">Tags</h2>
 
     <ul class="list-reset flex flex-wrap">
         {% for tag in page.tags|sort %}