diff --git a/core/themes/bartik/css/style.css b/core/themes/bartik/css/style.css
index 95155cd..72132ab 100644
--- a/core/themes/bartik/css/style.css
+++ b/core/themes/bartik/css/style.css
@@ -1261,6 +1261,15 @@ div.tabs {
   font-family: "Helvetica Neue", Helvetica, Arial, sans-serif;
   margin-bottom: 20px;
 }
+@media screen and (min-width: 37.5em) { /* 600px */
+  .is-horizontal .tabs__tab {
+    float: left; /* LTR */
+  }
+  [dir="rtl"] .is-horizontal .tabs__tab {
+    float: right;
+  }
+}
+
 .tabs--primary {
   border-collapse: collapse;
   height: auto;
@@ -1270,10 +1279,7 @@ div.tabs {
   border: none;
   white-space: nowrap;
 }
-.is-horizontal .tabs--primary li {
-  float: left;
-}
-.tabs--primary li {
+.tabs--primary .tabs__tab {
   display: block;
   vertical-align: bottom;
   margin: 0 5px 0 0; /* LTR */
@@ -1282,10 +1288,10 @@ div.tabs {
   margin: 0 0 0 5px;
   zoom: 1;
 }
-.tabs--primary li.active a {
+.tabs--primary .tabs__tab.active a {
   border-bottom: 1px solid #ffffff;
 }
-.tabs--primary li a {
+.tabs--primary .tabs__tab a {
   color: #000;
   background-color: #ededed;
   border-color: #bbb;
@@ -1299,7 +1305,7 @@ div.tabs {
   margin: 0;
   text-shadow: 0 1px 0 #fff;
 }
-.tabs--primary li.active a {
+.tabs--primary .tabs__tab.active a {
   background-color: #ffffff;
   border: 1px solid #bbb;
   border-bottom: 1px solid #fff;
@@ -1309,36 +1315,24 @@ div.tabs {
     background: transparent url(../images/tabs-border.png) repeat-x left bottom;
     padding: 0 3px;
   }
-  .tabs--primary li {
-    float: left; /* LTR */
-  }
-  [dir="rtl"] .tabs--primary .tabs__tab {
-    float: right;
-  }
-  .tabs--primary li.active a {
-
-  }
-  .tabs--primary li a {
+  .tabs--primary .tabs__tab a {
     float: left; /* not LTR */
     border-top-left-radius: 6px;
     border-top-right-radius: 6px;
   }
-  .tabs--primary li.active a {
-
-  }
 }
 @media screen and (max-width: 37.5em) { /* 600px */
   .tabs--primary {
     border-bottom: 1px solid #bbb;
   }
-  .tabs--primary li {
+  .tabs--primary .tabs__tab {
     display: block;
     margin: 0;
   }
-  .tabs--primary li a {
+  .tabs--primary .tabs__tab a {
     padding: 5px 10px;
   }
-  .tabs--primary li.active a {
+  .tabs--primary .tabs__tab.active a {
     border-bottom: none;
   }
 }
@@ -1347,28 +1341,26 @@ div.tabs {
   margin: 5px;
   padding: 0.5em 0;
 }
-.tabs--secondary li {
+.tabs--secondary .tabs__tab {
   border-right: 1px solid #ccc; /* LTR */
   display: block;
-  float: left; /* LTR */
   margin: 0;
   padding: 0 1em;
 }
-[dir="rtl"] .tabs--secondary li {
+[dir="rtl"] .tabs--secondary .tabs__tab {
   border-left: 1px solid #ccc;
   border-right: none;
-  float: right;
 }
-.tabs--secondary li:last-child {
+.tabs--secondary .tabs__tab:last-child {
   border-right: none; /* LTR */
 }
-[dir="rtl"] .tabs--secondary li:last-child {
+[dir="rtl"] .tabs--secondary .tabs__tab:last-child {
   border-left: none;
 }
-.tabs--secondary li:first-child {
+.tabs--secondary .tabs__tab:first-child {
   padding-left: 0; /* LTR */
 }
-[dir="rtl"] .tabs--secondary li:first-child {
+[dir="rtl"] .tabs--secondary .tabs__tab:first-child {
   padding-right: 0;
 }
 .tabs--secondary a {
diff --git a/core/themes/bartik/templates/menu-local-tasks.html.twig b/core/themes/bartik/templates/menu-local-tasks.html.twig
index 90281b5..0f57421 100644
--- a/core/themes/bartik/templates/menu-local-tasks.html.twig
+++ b/core/themes/bartik/templates/menu-local-tasks.html.twig
@@ -17,11 +17,13 @@
 #}
 {% if primary %}
   <h2 class="visually-hidden">{{ 'Primary tabs'|t }}</h2>
-<nav role="navigation">
-  <ul class="tabs tabs--primary clearfix">{{ primary }}</ul>
-  {% endif %}
-  {% if secondary %}
+  <nav role="navigation" class="is-horizontal">
+    <ul class="tabs tabs--primary">{{ primary }}</ul>
+  </nav>
+{% endif %}
+{% if secondary %}
   <h2 class="visually-hidden">{{ 'Secondary tabs'|t }}</h2>
-  <ul class="tabs tabs--secondary clearfix">{{ secondary }}</ul>
-</nav>
+  <nav role="navigation" class="is-horizontal">
+    <ul class="tabs tabs--secondary">{{ secondary }}</ul>
+  </nav>
 {% endif %}