diff --git a/starshot_demo/starshot_demo.theme b/starshot_demo/starshot_demo.theme
new file mode 100644
index 0000000000000000000000000000000000000000..07256616aa3c379916edaaadd22906100b34df04
--- /dev/null
+++ b/starshot_demo/starshot_demo.theme
@@ -0,0 +1,16 @@
+<?php
+
+/**
+ * @file
+ * Functions to support theming in the Starshot Demo theme.
+ */
+
+/**
+ * Implements hook_preprocess_page().
+ */
+function starshot_demo_preprocess_page(array &$variables): void {
+
+  // Do not strip out Drupal core styles.
+  $variables['modifier_class'] = FALSE;
+
+}