diff --git a/src/_includes/partials/page-header/navigation-triggers.css b/src/_includes/partials/page-header/navigation-triggers.css
index d542a9dd..9f0d1271 100644
--- a/src/_includes/partials/page-header/navigation-triggers.css
+++ b/src/_includes/partials/page-header/navigation-triggers.css
@@ -75,12 +75,17 @@
   outline-offset: -2px;
 }
 
+@media all and (max-width: 60.124em) {
+  .navigation-opened .navigation-list-item--toplevel > a {
+    flex: 1 1 auto;
+  }
+}
+
 .navigation-submenu-toggle[aria-expanded="true"] + .navigation-list--sublevel {
     display: block;
     width: 100%;
 }
 
-
 @media all and (min-width: 60.125em) {
     .navigation-submenu-toggle[aria-expanded="true"] + .navigation-list--sublevel {
         width: auto;