change h2 into div

_layouts/post.html

@@ -2,14 +2,16 @@
 layout: default
 ---
 <article class="post">
-    <header class="post-header wrapper">
-        <h2 class="post-title">
+    <header class="post-header">
+        <div class="post-title wrapper">
+            <h2>
                 {% if page.external-url %}
                     <a href="{{ page.external-url }}">{{ page.title }}</a>
                 {% else %}
                     {{ page.title }}
                 {% endif %}
             </h2>
+        </div>
         <p class="public-date">vom <time class="page-date" datetime="{{ page.date | date: "%Y-%m-%d"}}">
                 {% assign m = page.date | date: "%-m" %}
                 {{ page.date | date: "%d" }}