Fixed mobile placeholders / CSS support

src/_includes/layout.html

@@ -54,7 +54,7 @@
       <div class="nav-hyperlinks">
         <ul>
           <li data-mobile>
-            <button class="hamburger" aria-label="Toggle menu">
+            <button id="mobile-nav-btn" class="hamburger" aria-label="Toggle menu">
               <ion-icon name="menu-sharp"></ion-icon>
             </button>
           </li>
@@ -175,5 +175,8 @@
 
   <script type="module" src="https://unpkg.com/ionicons@7.1.0/dist/ionicons/ionicons.esm.js"></script>
   <script nomodule src="https://unpkg.com/ionicons@7.1.0/dist/ionicons/ionicons.js"></script>
+  <script>
+    document.getElementById('mobile-nav-btn').addEventListener('click', () => alert('Not yet implemented!'));
+  </script>
 </body>
 </html>