Issue # 3243658: CSS fixes for the top collapsed menu

scss/regions/_header.scss

@@ -165,6 +165,15 @@ header {
   }
 }
 
+#navbar-collapse {
+  .region-navigation-collapsible {
+    display: flex;
+    flex-direction: row;
+    justify-content: center;
+    padding: 10px 0px;
+  }
+}
+
 @include media-breakpoint-down(xs) {
   .region-navigation-collapsible {
     width: 100%;
@@ -177,6 +186,7 @@ header {
 
 .navbar-collapse {
   float: right;
+
   @include media-breakpoint-down(xs) {
     width: 100%;
     text-align: center;