diff --git a/scss/_root.scss b/scss/_root.scss
index ab0584e68a..4d5f3d198e 100644
--- a/scss/_root.scss
+++ b/scss/_root.scss
@@ -56,6 +56,7 @@
   --#{$variable-prefix}border-style: solid;
   --#{$variable-prefix}border-color: #{$border-color};
   --#{$variable-prefix}border-radius: #{$border-radius};
+  --#{$variable-prefix}border-opacity: 1;
   // scss-docs-end root-border-var
   // stylelint-enable custom-property-empty-line-before
 }