diff --git a/_config.yml b/_config.yml
index 806eb21cee..b6c2952b14 100644
--- a/_config.yml
+++ b/_config.yml
@@ -853,6 +853,16 @@ pdf:
     # CDNJS, provided by cloudflare, maybe the best CDN, but not works in China
     #cdn: //cdnjs.cloudflare.com/ajax/libs/pdfobject/2.1.1/pdfobject.min.js
 
+# Mermaid tag
+mermaid:
+  enable: false
+  # Available themes: default | dark | forest | neutral
+  theme: forest
+  # Use 8.0.0 as default, jsdelivr as default CDN, works everywhere even in China
+  cdn: //cdn.jsdelivr.net/npm/mermaid@8/dist/mermaid.min.js
+  # CDNJS, provided by cloudflare, maybe the best CDN, but not works in China
+  #cdn: //cdnjs.cloudflare.com/ajax/libs/mermaid/8.0.0/mermaid.min.js
+
 
 #! ---------------------------------------------------------------
 #! DO NOT EDIT THE FOLLOWING SETTINGS
@@ -879,16 +889,16 @@ motion:
     sidebar: slideUpIn
 
 # Fancybox. There is support for old version 2 and new version 3.
-# Choose only any one variant, do not need to install both.
+# Choose only one variant, do not need to install both.
 # To install 2.x: https://github.com/theme-next/theme-next-fancybox
 # To install 3.x: https://github.com/theme-next/theme-next-fancybox3
 fancybox: false
 
-# Added switch option for separated repo in 6.0.0.
+# Polyfill to remove click delays on browsers with touch UIs.
 # Dependencies: https://github.com/theme-next/theme-next-fastclick
 fastclick: false
 
-# Added switch option for separated repo in 6.0.0.
+# Vanilla JavaScript plugin for lazyloading images.
 # Dependencies: https://github.com/theme-next/theme-next-jquery-lazyload
 lazyload: false
 
diff --git a/layout/_layout.swig b/layout/_layout.swig
index f388169203..a273ee9cdf 100644
--- a/layout/_layout.swig
+++ b/layout/_layout.swig
@@ -110,6 +110,7 @@
   {% include '_third-party/analytics/firestore.swig' %}
   {% include '_third-party/math/index.swig' %}
   {% include '_third-party/pdf.swig' %}
+  {% include '_third-party/mermaid.swig' %}
   {% include '_third-party/baidu-push.swig' %}
   {% include '_third-party/schedule.swig' %}
   {% include '_third-party/needsharebutton.swig' %}
diff --git a/layout/_third-party/mermaid.swig b/layout/_third-party/mermaid.swig
new file mode 100644
index 0000000000..a7859a6d4f
--- /dev/null
+++ b/layout/_third-party/mermaid.swig
@@ -0,0 +1,21 @@
+{% if theme.mermaid.enable %}
+<script>
+if ($('body').find('pre.mermaid').length) {
+  $.ajax({
+    type: 'GET',
+    url: '{{ theme.mermaid.cdn }}',
+    dataType: 'script',
+    cache: true,
+    success: function() {
+      mermaid.initialize({
+        theme: '{{ theme.mermaid.theme }}',
+        logLevel: 3,
+        flowchart: { curve: 'linear' },
+        gantt: { axisFormat: '%m/%d/%Y' },
+        sequence: { actorMargin: 50 }
+      });
+    }
+  });
+}
+</script>
+{% endif %}
diff --git a/scripts/tags/mermaid.js b/scripts/tags/mermaid.js
new file mode 100644
index 0000000000..7b5aae6a6c
--- /dev/null
+++ b/scripts/tags/mermaid.js
@@ -0,0 +1,16 @@
+/**
+ * mermaid.js | https://theme-next.org/docs/tag-plugins/mermaid/
+ */
+
+/* global hexo */
+
+'use strict';
+
+function mermaid(args, content) {
+  return `<pre class="mermaid" style="text-align: center;">
+            ${args.join(' ')}
+            ${content}
+          </pre>`;
+}
+
+hexo.extend.tag.register('mermaid', mermaid, {ends: true});
diff --git a/source/js/src/js.cookie.js b/source/js/src/js.cookie.js
index c6c3975831..97b4fea1de 100644
--- a/source/js/src/js.cookie.js
+++ b/source/js/src/js.cookie.js
@@ -5,6 +5,7 @@
  * Copyright 2006, 2015 Klaus Hartl & Fagner Brack
  * Released under the MIT license
  */
+
 ;(function (factory) {
 	var registeredInModuleLoader = false;
 	if (typeof define === 'function' && define.amd) {