diff --git a/scss/helper.scss b/scss/helper.scss
index 0c6827842..57c0d4fb6 100644
--- a/scss/helper.scss
+++ b/scss/helper.scss
@@ -47,6 +47,7 @@
 @import './helper/box-alignment/place-self';
 
 @import './helper/effect/box-shadow';
+@import './helper/effect/opacity';
 
 @import './helper/spacing/margin';
 @import './helper/spacing/padding';