diff --git a/core/themes/seven/style.css b/core/themes/seven/style.css
index 373601c..cdd0429 100644
--- a/core/themes/seven/style.css
+++ b/core/themes/seven/style.css
@@ -322,6 +322,7 @@ pre {
   color: #008ee6;
   background-color: #fafaf7;
 }
+
 /* TODO: Move the tabs__tab class to the anchor instead of having to reset the padding. */
 li.tabs__tab {
   padding: 0;
@@ -376,6 +377,9 @@ li.tabs__tab a {
  * JS dependent styling
  */
  .is-collapse-enabled .tabs__trigger {
+  -webkit-box-sizing: content-box;
+  -moz-box-sizing:    content-box;
+  box-sizing:         content-box;
   display: block;
   position: absolute;
   z-index: 10;
@@ -383,22 +387,20 @@ li.tabs__tab a {
   top: 2px;
   left: auto;
   width: 25%;
-  padding-right: 1em;
+  padding-right: 4px;
+  padding-left: 4px;
   border-left: 0;
   border-radius: 0 4px 0 0;
   font-family: Arial, sans-serif;
   font-size: 1.25em;
   letter-spacing: 0.1em;
   text-align: center;
+  outline: 0;
 }
 /* TODO: Make this number less magic */
 .is-collapse-enabled .tabs {
   padding-top: 38px;
   max-height: 0;
-  -webkit-transition: max-height 0.15s ease-in-out;
-  -moz-transition:    max-height 0.15s ease-in-out;
-  -o-transition:      max-height 0.15s ease-in-out;
-  transition:         max-height 0.15s ease-in-out;
 }
 .tabs.is-open {
   max-height: 999em;
@@ -444,6 +446,7 @@ li.tabs__tab a {
   width: auto;
   top: 0;
   border-bottom: 0;
+  margin: 0 -4px;
 }
 .is-horizontal .tabs.primary a {
   background-image: none;