Implement proper mobile navigation

app/javascript/controllers/topbar_controller.js

@@ -0,0 +1,31 @@
+import { Controller } from "@hotwired/stimulus"
+
+function show (element) {
+  element.classList.add('block');
+  element.classList.remove('hidden');
+}
+
+function  hide (element) {
+  element.classList.remove('block');
+  element.classList.add('hidden');
+}
+
+export default class extends Controller {
+  static targets = [ 'mobileMenu', 'iconMobileMenuOpen', 'iconMobileMenuClose' ];
+
+  connect() {
+    this.mobileMenuTarget.classList.add('hidden');
+  }
+
+  toggleMobileNav() {
+    if (this.mobileMenuTarget.classList.contains('hidden')) {
+      show(this.mobileMenuTarget);
+      show(this.iconMobileMenuCloseTarget);
+      hide(this.iconMobileMenuOpenTarget);
+    } else {
+      hide(this.mobileMenuTarget);
+      hide(this.iconMobileMenuCloseTarget);
+      show(this.iconMobileMenuOpenTarget);
+    }
+  }
+}