diff --git a/agaric/templates/block/block--highlighted.html.twig b/agaric/templates/block/block--highlighted.html.twig
index 862700b..f63c53c 100644
--- a/agaric/templates/block/block--highlighted.html.twig
+++ b/agaric/templates/block/block--highlighted.html.twig
@@ -7,7 +7,7 @@
 %}
 {% set attributes = attributes.addClass(classes).setAttribute('data-headerbg', 'light') %}
 <section{{ attributes }}>
-  <div class="hero-body subtitle is-mono is-4">
+  <div class="hero-body subtitle is-mono is-4 container">
     {{ title_prefix }}
     {% if label %}
       <h2{{ title_attributes }}>{{ label }}</h2>