diff --git a/docs/theming/customizing.md b/docs/theming/customizing.md
index c8d8ce1cfc..c13d7b124c 100644
--- a/docs/theming/customizing.md
+++ b/docs/theming/customizing.md
@@ -23,7 +23,7 @@ order: 3
   import '@rhds/elements/rh-tag/rh-tag.js';
   import '@rhds/elements/rh-tile/rh-tile.js';
   document.getElementById('bordeaux-page-switch').addEventListener('change', function() {
-    document.body.classList.toggle('theme-bordeaux', this.checked);
+    document.documentElement.classList.toggle('theme-bordeaux', this.checked);
   });
 </script>