diff --git a/core/css/styles.scss b/core/css/styles.scss
index 1269796b266a8..8996bee1cc300 100644
--- a/core/css/styles.scss
+++ b/core/css/styles.scss
@@ -818,7 +818,7 @@ span.ui-icon {
 	}
 
 	.content {
-		max-height: calc(100% - $header-height);
+		max-height: calc(100% - #{$header-height});
 		height: 100%;
 		overflow-y: auto;