Adjusted the active state to fix the faint line showing. Probably related to the font change going into 4.0 (#6886)

public/sass/components/_tabs.scss

@@ -65,6 +65,6 @@
     border-bottom: 2px solid $panel-bg;
     color: $link-color;
     position: relative;
-    top: 2px;
+    top: 1px;
   }
 }