Sync: implement menu toggle functionality to manage body overflow state

theme/assets/css/main.css

@@ -493,6 +493,10 @@ p:last-child { margin-bottom: 0; }
     z-index: 99;
     padding: 5rem 2rem 2rem;
     overflow-y: auto;
+    -webkit-overflow-scrolling: touch;
+  }
+  body.menu-open {
+    overflow: hidden;
   }
   .site-nav.open .nav-menu {
     flex-direction: column;

theme/assets/js/main.js

@@ -39,6 +39,7 @@ document.addEventListener('DOMContentLoaded', () => {
     toggle.addEventListener('click', () => {
       toggle.classList.toggle('open');
       nav.classList.toggle('open');
+      document.body.classList.toggle('menu-open');
       const expanded = toggle.getAttribute('aria-expanded') === 'true';
       toggle.setAttribute('aria-expanded', !expanded);
     });