change align strategy

templates/default.html.twig

@@ -1,11 +1,13 @@
 {% extends 'partials/base.html.twig' %}
 
 {% block content %}
-    {% if page.header.left %}
-        <div class="left">
+    {% if page.header.center %}
+        <div>
         {{ page.content | raw }}
         </div> 
     {% else %}
+        <div class="left">
         {{ page.content|raw }}
+        </div>
     {% endif %}
 {% endblock %}