fix centering again

shared/templates/styleguide2/includes/atoms/youtube_video/youtube_video.html

@@ -58,6 +58,10 @@
     {% else %}
       max-w-[100ch]
     {% endif %}
+
+    {% if page.root_page.content_is_centered %}
+      mx-auto
+    {% endif %}
   "
   id="ytVideo{{ self.video_id }}IframeContainer"
   style="display: none"