diff --git a/gtk/gtkinfobar.c b/gtk/gtkinfobar.c
index 01f0f48307..919b95cdfa 100644
--- a/gtk/gtkinfobar.c
+++ b/gtk/gtkinfobar.c
@@ -119,6 +119,12 @@
  * multiple <action-widget> elements. The “response” attribute specifies a
  * numeric response, and the content of the element is the id of widget
  * (which should be a child of the dialogs @action_area).
+ *
+ * # CSS nodes
+ *
+ * GtkInfoBar has a single CSS node with name infobar. The node may get
+ * one of the style classes .info, warning, .error or .question, depending
+ * on the message type.
  */
 
 enum
@@ -585,6 +591,8 @@ gtk_info_bar_class_init (GtkInfoBarClass *klass)
   gtk_widget_class_bind_template_child_internal_private (widget_class, GtkInfoBar, action_area);
   gtk_widget_class_bind_template_child_internal_private (widget_class, GtkInfoBar, close_button);
   gtk_widget_class_bind_template_child_internal_private (widget_class, GtkInfoBar, revealer);
+
+  gtk_widget_class_set_css_name (widget_class, "infobar");
 }
 
 static void