diff --git a/core/themes/bartik/css/colors.css b/core/themes/bartik/css/colors.css
index cbec545..4e70c3d 100644
--- a/core/themes/bartik/css/colors.css
+++ b/core/themes/bartik/css/colors.css
@@ -13,7 +13,7 @@ body {
 .tabs--primary li a.is-active {
   background-color: #ffffff;
 }
-.tabs--primary li.is-active a {
+.tabs--primary li.active a {
   background-color: #ffffff;
   border-bottom-color: #ffffff;
 }
diff --git a/core/themes/bartik/css/components/tabs.css b/core/themes/bartik/css/components/tabs.css
index 9f54209..11fe831 100644
--- a/core/themes/bartik/css/components/tabs.css
+++ b/core/themes/bartik/css/components/tabs.css
@@ -42,7 +42,7 @@
   margin: 0;
   text-shadow: 0 1px 0 #fff;
 }
-.tabs--primary li.is-active a {
+.tabs--primary li.active a {
   background-color: #fff;
   border: 1px solid #bbb;
   border-bottom: 1px solid #fff;
@@ -68,7 +68,7 @@
   .tabs--primary .tabs__tab a {
     padding: 5px 10px;
   }
-  .tabs--primary li.is-active a {
+  .tabs--primary li.active a {
     border-bottom: none;
   }
 }
diff --git a/core/themes/seven/css/components/tabs.css b/core/themes/seven/css/components/tabs.css
index 7f38ec9..25617ab 100644
--- a/core/themes/seven/css/components/tabs.css
+++ b/core/themes/seven/css/components/tabs.css
@@ -269,7 +269,7 @@
   padding: 7px 13px 5px;
   text-decoration: none;
 }
-.tabs--secondary .is-active a {
+.tabs--secondary .active a {
   color: #004f80;
 }
 .tabs--secondary a:focus {