diff --git a/core/css/header.scss b/core/css/header.scss
index cc4232ccd2bb3..b5e73633b8c6d 100644
--- a/core/css/header.scss
+++ b/core/css/header.scss
@@ -609,8 +609,7 @@ nav[role='navigation'] {
 		height: 34px;
 		width: 0;
 		cursor: pointer;
-		-webkit-transition: all 100ms;
-		transition: all 100ms;
+		transition: width 100ms, opacity 100ms;
 		opacity: .6;
 		&:focus, &:active, &:valid {
 			background-position-x: 6px;