ADA-235: Improve skip link hover and focus color (#60)

Author: yzhoubk

app/assets/stylesheets/_customizations.scss

@@ -43,4 +43,10 @@ ul.facet-values {
       text-decoration: underline;
     }
   }
+}
+
+.element-focusable:hover,
+.element-focusable:focus {
+  color: #0051AD;
+  text-decoration: underline;
 }