refactor: Modify animation of heading

source/css/_common/components/sidebar/index.styl

 .sidebar {
   width: convert(hexo-config('sidebar.width') || '$sidebar-width');
 
+  &.sticky {
+    position: fixed;
+    top: convert(hexo-config('sidebar.offsetTop') || '30px');
+    z-index: $z-index0;
+    transform: translateZ(0);
+  }
+
   .hide {
     display: none;
   }

source/css/_common/outline/macro.styl

@@ -29,13 +29,6 @@
 if (hexo-config('sidebar.enable')) {
   .sidebar {
     float: convert(hexo-config('sidebar.position'));
-
-    &.sticky {
-      position: fixed;
-      top: convert(hexo-config('sidebar.offsetTop') || '30px');
-      z-index: $z-index0;
-      transform: translateZ(0);
-    }
   }
 }
 

source/css/_variables/index.styl

@@ -131,7 +131,7 @@ $category-list-dot-color           = $blue-light
 $category-list-dot-hover-color     = $orange-dark
 $category-post-count-color         = #99a9bf
 $category-link-color               = $blue-light
-$category-link-hover-color         = $blue-light
+$category-link-hover-color         = $orange-dark
 
 // Tag page
 $tag-hover-color                   = $orange-dark

source/js/scroll.js

@@ -45,7 +45,10 @@ $(document).ready(function () {
   function scrollHeadingToTop (anchor) {
     $(anchor)
       .velocity('stop')
-      .velocity('scroll', { easing: 'easeOutSine' });
+      .velocity('scroll', {
+        easing: 'ease-in-out',
+        duration: 600
+      });
   }
 
   var isBack2topShow = false;

source/js/sidebar.js

@@ -83,19 +83,21 @@ $(document).ready(function () {
   // Distance from sidebar to top.
   var SIDEBAR_STICKY_TOP = parseInt(CONFIG.sidebar.offsetTop);
   var isSidebarSticky = false;
-
+  
   // Sticky the sidebar when it arrived the top.
   function sidebarSticky () {
-    var targetY = $('#main')[0].getBoundingClientRect().top;
+    var $sidebar = $('#sidebar');
+    var targetY =
+      document.getElementById('main').getBoundingClientRect().top;
 
     if (targetY < SIDEBAR_STICKY_TOP) {
       if (!isSidebarSticky) {
-        $('#sidebar').addClass('sticky');
+        $sidebar.addClass('sticky');
         isSidebarSticky = true;
       }
     } else {
       if (isSidebarSticky) {
-        $('#sidebar').removeClass('sticky');
+        $sidebar.removeClass('sticky');
         isSidebarSticky = false;
       }
     }