diff --git a/agaric/templates/layout/page.html.twig b/agaric/templates/layout/page.html.twig
index 9ae8197..43003ce 100644
--- a/agaric/templates/layout/page.html.twig
+++ b/agaric/templates/layout/page.html.twig
@@ -35,7 +35,7 @@
 {% endif %}
 {% endblock navbar %}
 
-{% set header_section_attributes = create_attribute({'class': ['hero', 'is-dark']) %}
+{% set header_section_attributes = create_attribute({'class': ['hero', 'is-dark']}) %}
 {% if false %}
   {% set header_section_attributes = header_section_attributes.removeClass('is-dark').setAttribute('data-headerbg', 'light') %}
 {% endif %}