diff --git a/source/packages/com_mokosuitebackup/tmpl/runbackup/default.php b/source/packages/com_mokosuitebackup/tmpl/runbackup/default.php
index 235d1c04..d15582c5 100644
--- a/source/packages/com_mokosuitebackup/tmpl/runbackup/default.php
+++ b/source/packages/com_mokosuitebackup/tmpl/runbackup/default.php
@@ -90,6 +90,9 @@ $config = [
 ];
 ?>
 <style>
+	/* Full-screen backup runs on a black backdrop. */
+	html, body { background-color: #000 !important; }
+
 	/* Colours are pulled from the Atum admin template's own CSS custom
 	   properties so the screen matches whatever theme the site runs, with
 	   Bootstrap and then a literal as progressive fallbacks. */