script and css to change nav background

src/js/main.js

@@ -1,3 +1,4 @@
+//toggle menu burger animation
 document.getElementById("menuToggle").addEventListener("click", menuToggle);
 function menuToggle() {
   var bars = document.getElementsByClassName('bar');
@@ -5,3 +6,12 @@ function menuToggle() {
     bars[i].classList.toggle('active');
   }
 }
+
+//toggle nav backgroundcolor
+window.addEventListener('scroll', function() {
+  if (window.pageYOffset == 0) {
+    document.getElementById("nav").classList.remove('scrolled');
+  } else {
+    document.getElementById("nav").classList.add('scrolled');
+  }
+});