diff --git a/assets/style.scss b/assets/style.scss
index a15909b..739401b 100644
--- a/assets/style.scss
+++ b/assets/style.scss
@@ -80,7 +80,7 @@ body {
 		pointer-events: none;
 		background-image: url('layout/fg_pixels.gif');
 		background-repeat: repeat-y;
-		background-position: 50% calc(50% + -1.4px * var(--scrollTop));
+		background-position: 50% calc(50% + -1.4px * var(--scrollTop, 0));
 	}
 
 	@media (min-width: $small) {