diff --git a/core/css/header.scss b/core/css/header.scss
index 32e8386ee0..e744d3acb4 100644
--- a/core/css/header.scss
+++ b/core/css/header.scss
@@ -137,18 +137,18 @@
 		vertical-align: middle;
 	}
 
-	.header-left,
-	.header-right {
+	#header-left, .header-left,
+	#header-right, .header-right {
 		display: inline-flex;
 		align-items: center;
 	}
 
-	.header-left {
+	#header-left, .header-left {
 		flex: 0 0;
 		flex-grow: 1;
 	}
 
-	.header-right {
+	#header-right, .header-right {
 		justify-content: flex-end;
 	}
 }