feat: Reveal 'Top of Page' only on scroll

[ci skip]

client/scss/base/base.scss

@@ -72,6 +72,15 @@ a {
   display: none !important;
 }
 
+.is-hidden-until-scroll {
+  max-height: 0;
+  overflow: hidden;
+  transition: all .6s ease;
+}
+.is-sticky .is-hidden-until-scroll {
+  max-height: 30px;
+}
+
 .is-hidden-mobile {
   @include mobile {
     display: none !important;

server/views/pages/view.pug

@@ -65,7 +65,7 @@ block content
             .sidebar-label
               span Page Contents
             ul.sidebar-menu
-              li: a(href='#root', title='Top of Page')
+              li.is-hidden-until-scroll: a(href='#root', title='Top of Page')
                 i.icon-arrow-up2
               +tocMenu(pageData.tree)