fix sign up nav

public/scripts/register.js

@@ -1,6 +1,22 @@
 var counter = 1;
 $(document).ready(function() {
 
+  // navigation bar toggle
+  $('#navbar-toggler').click(function(){
+    $('.navbar-collapse').slideToggle(400);
+  });
+
+  // navbar bg change on scroll
+  $(window).scroll(function(){
+      let pos = $(window).scrollTop();
+      if(pos >= 100){
+          $('.navbar').addClass('cng-navbar');
+      } else {
+          $('.navbar').removeClass('cng-navbar');
+      }
+  });
+
+
   var erroEle = $('.error-message'),
     focusInput = $('.questions').find('.active');