make navbar sticky

src/client/styles/scss/_layout.scss

@@ -14,10 +14,6 @@ body {
   font-weight: bold;
 }
 
-#page-wrapper {
-  margin-top: $grw-navbar-height + $grw-navbar-border-width;
-}
-
 .grw-modal-head {
   font-size: 1em;
   border-bottom: 1px solid $gray-500;

src/client/styles/scss/_navbar.scss

@@ -1,4 +1,6 @@
 .grw-navbar {
+  top: -$grw-navbar-height !important;
+
   max-height: $grw-navbar-height + $grw-navbar-border-width;
   border-top: 0;
   border-right: 0;

src/server/views/layout/layout.html

@@ -76,7 +76,7 @@
 <div id="wrapper">
 
   {% block layout_head_nav %}
-  <nav class="navbar grw-navbar navbar-expand navbar-dark fixed-top mb-0 px-0">
+  <nav class="navbar grw-navbar navbar-expand navbar-dark sticky-top mb-0 px-0">
     {# Brand Logo #}
     <div class="navbar-brand mr-0">
       <a class="grw-logo d-block" href="/">