diff --git a/themes/atom-dark-ui/wrap-guide.css b/themes/atom-dark-ui/wrap-guide.css
index 51660ea4c..8e7837e5d 100644
--- a/themes/atom-dark-ui/wrap-guide.css
+++ b/themes/atom-dark-ui/wrap-guide.css
@@ -1,3 +1,3 @@
 .wrap-guide {
-  background: rgba(150, 150, 150, .30);
+  background: rgba(150, 150, 150, 0.1);
 }
diff --git a/themes/atom-light-ui/wrap-guide.css b/themes/atom-light-ui/wrap-guide.css
index 51660ea4c..f4ff6269c 100644
--- a/themes/atom-light-ui/wrap-guide.css
+++ b/themes/atom-light-ui/wrap-guide.css
@@ -1,3 +1,3 @@
 .wrap-guide {
-  background: rgba(150, 150, 150, .30);
+  background: rgba(150, 150, 150, 0.3);
 }