diff --git a/browser/themes/linux/browser.css b/browser/themes/linux/browser.css
index db1360bb9f87..6d2e3d6c8895 100644
--- a/browser/themes/linux/browser.css
+++ b/browser/themes/linux/browser.css
@@ -18,8 +18,8 @@
   --toolbarbutton-icon-fill-opacity: .85;
 
   --panel-separator-color: ThreeDShadow;
-  --arrowpanel-dimmed: hsla(0,0%,80%,.3);
-  --arrowpanel-dimmed-further: hsla(0,0%,80%,.45);
+  --arrowpanel-dimmed: hsla(0,0%,80%,.35);
+  --arrowpanel-dimmed-further: hsla(0,0%,80%,.5);
   --arrowpanel-dimmed-even-further: hsla(0,0%,80%,.8);
 
   --urlbar-separator-color: ThreeDShadow;
diff --git a/browser/themes/osx/browser.css b/browser/themes/osx/browser.css
index 74da0879f1d9..474edc2b6cda 100644
--- a/browser/themes/osx/browser.css
+++ b/browser/themes/osx/browser.css
@@ -19,8 +19,8 @@
   --toolbarbutton-icon-fill-opacity: .7;
 
   --panel-separator-color: hsla(210,4%,10%,.14);
-  --arrowpanel-dimmed: hsla(0,0%,80%,.3);
-  --arrowpanel-dimmed-further: hsla(0,0%,80%,.45);
+  --arrowpanel-dimmed: hsla(0,0%,80%,.35);
+  --arrowpanel-dimmed-further: hsla(0,0%,80%,.5);
   --arrowpanel-dimmed-even-further: hsla(0,0%,80%,.8);
 
   --arrowpanel-field-background: rgba(249,249,250,.3);
diff --git a/browser/themes/windows/browser.css b/browser/themes/windows/browser.css
index 21c3fb02862a..9419a6e70135 100644
--- a/browser/themes/windows/browser.css
+++ b/browser/themes/windows/browser.css
@@ -18,8 +18,8 @@
   --toolbarbutton-icon-fill-opacity: 1;
 
   --panel-separator-color: ThreeDLightShadow;
-  --arrowpanel-dimmed: hsla(0,0%,80%,.3);
-  --arrowpanel-dimmed-further: hsla(0,0%,80%,.45);
+  --arrowpanel-dimmed: hsla(0,0%,80%,.35);
+  --arrowpanel-dimmed-further: hsla(0,0%,80%,.5);
   --arrowpanel-dimmed-even-further: hsla(0,0%,80%,.8);
 
   --urlbar-separator-color: ThreeDLightShadow;