diff --git a/config.toml b/config.toml
index 6f6b5d2..066de4a 100644
--- a/config.toml
+++ b/config.toml
@@ -9,6 +9,7 @@ feed_filenames = ["rss.xml"]
 
 [markdown]
 highlighting = { theme = "GitHub-Dark" }
+external_links_target_blank = true
 
 [extra]
 author = "Yan Lin"
diff --git a/templates/base.html b/templates/base.html
index a19dfe5..81a23d0 100644
--- a/templates/base.html
+++ b/templates/base.html
@@ -30,7 +30,7 @@
         <nav>
             <a href="{{ get_url(path='/') }}" class="site-title">{{ config.title }}</a>
             {% set root = get_section(path="_index.md") %}
-            {% for path in root.subsections %}
+            {% for path in root.subsections | sort %}
             {% set s = get_section(path=path) %}
             <a href="{{ s.permalink }}">{{ s.title }}</a>
             {% endfor %}