diff --git a/ui/stylesheets/csui/_details.scss b/ui/stylesheets/csui/_details.scss
index 2ef9417df35..70cdaefd79a 100644
--- a/ui/stylesheets/csui/_details.scss
+++ b/ui/stylesheets/csui/_details.scss
@@ -15,6 +15,8 @@
 // specific language governing permissions and limitations
 // under the License.
 
+$csui-tab-bg: lighten(#ccc, 15%);
+
 @mixin csui-tab {
     float: left;
     list-style: none;
@@ -30,7 +32,7 @@
 }
 
 @mixin csui-tab-active {
-    background: lighten(#ccc, 15%);
+    background: $csui-tab-bg;
     border-radius: 8px 8px 0 0;
     margin: 0;
 
@@ -53,7 +55,7 @@
 }
 
 @mixin csui-details {
-    background: lighten(#ccc, 15%);
+    background: $csui-tab-bg;
     padding: 10px;
     border-bottom: 1px solid #ccc;
 }