Use more specific querySelector

Co-authored-by: Stefano Ottolenghi <stefano.ottolenghi@neo4j.com>

Author: recrwplay

src/js/01-nav.js

@@ -133,7 +133,7 @@
 
   function showNav (e) {
     if (navToggle.classList.contains('is-active')) return hideNav(e)
-    var html = document.documentElement.querySelector('main') || document.documentElement.querySelector('article') || document.documentElement
+    var html = document.documentElement.querySelector('main.article')
     html.classList.add('is-clipped--nav')
     navToggle.classList.add('is-active')
     navContainer.classList.add('is-active')