diff --git a/layout/_macro/sidebar.njk b/layout/_macro/sidebar.njk
index bae7322..f0a8c98 100644
--- a/layout/_macro/sidebar.njk
+++ b/layout/_macro/sidebar.njk
@@ -32,11 +32,12 @@
         <!--/noindex-->
 
         <div class="site-overview-wrap sidebar-panel">
-          {{ partial('_partials/sidebar/site-overview.njk', {}, {cache: theme.cache.enable}) }}
+          <div class="site-overview">
+            {{ partial('_partials/sidebar/site-overview.njk', {}, {cache: theme.cache.enable}) }}
 
-          {{- next_inject('sidebar') }}
+            {{- next_inject('sidebar') }}
+          </div>
         </div>
-      </div>
 
       {%- if theme.back2top.enable and theme.back2top.sidebar %}
         <div class="back-to-top animated" role="button" aria-label="{{ __('accessibility.back_to_top') }}">
diff --git a/source/css/_common/outline/sidebar/index.styl b/source/css/_common/outline/sidebar/index.styl
index c7fd162..a6195f4 100644
--- a/source/css/_common/outline/sidebar/index.styl
+++ b/source/css/_common/outline/sidebar/index.styl
@@ -4,6 +4,10 @@
   text-align: center;
 }
 
+.site-overview {
+  max-height: var(--sidebar-wrapper-height);
+}
+
 .site-overview-item:not(:first-child) {
   margin-top: 10px;
 }