diff --git a/docs/en/docs/assets/css/custom.css b/docs/en/docs/assets/css/custom.css
index f74aeeb0..37e63aab 100644
--- a/docs/en/docs/assets/css/custom.css
+++ b/docs/en/docs/assets/css/custom.css
@@ -1,5 +1,5 @@
 .md-typeset__table table {
-  font-size: .75rem !important;
+  font-size: 0.75rem !important;
 }
 
 .md-typeset__table table tr td:first-child {
@@ -8,16 +8,16 @@
 
 .md-typeset code {
   background-color: rgb(240, 240, 240);
-  font-size: .95em;
+  font-size: 0.95em;
 }
 
 .md-typeset pre > code {
   background-color: rgb(245, 245, 245);
-  font-size: .90em;
+  font-size: 0.9em;
 }
 
 .md-typeset .admonition {
-  font-size: .70rem;
+  font-size: 0.7rem;
 }
 
 body {
@@ -29,7 +29,7 @@ body {
   border-bottom-color: rgb(234, 236, 239);
   border-bottom-style: solid;
   border-bottom-width: 1px;
-  padding-bottom: .3rem;
+  padding-bottom: 0.3rem;
 }
 
 .md-content a:hover {
@@ -39,3 +39,22 @@ body {
 .highlight code .cp {
   color: #a83;
 }
+
+a code {
+  color: #472a63 !important;
+}
+
+[data-md-color-scheme="dark"] {
+  --md-primary-fg-color: #321860;
+  --md-default-bg-color: #170a1c;
+  --md-default-fg-color: #dabaff;
+  --md-typeset-color: #ffffff;
+  --md-default-fg-color--light: #b0a8b9;
+  --md-typeset-a-color: #b596d2;
+  --md-code-bg-color: #f5f5f5;
+  --md-code-fg-color: #170a1c;
+  --md-admonition-fg-color: #ffffff;
+  --md-default-fg-color--lighter: #acb7c0;
+  --md-default-fg-color--lightest: #d2d5db;
+  --md-code-hl-variable-color: #815abb;
+}
diff --git a/docs/en/mkdocs.yml b/docs/en/mkdocs.yml
index b3edf1c5..845be1c9 100644
--- a/docs/en/mkdocs.yml
+++ b/docs/en/mkdocs.yml
@@ -1,59 +1,70 @@
 # Project information
-site_name: 'Sailfish Documentation'
+site_name: "Sailfish Documentation"
 # site_description: 'Sailfish Documentation'
-site_author: 'Ryohei Machida'
+site_author: "Ryohei Machida"
 # site_url: 'https://***.com'
 
 # Copyright
-copyright: '© 2020 Ryohei Machida'
+copyright: "© 2020 Ryohei Machida"
 
 # Repository
-repo_name: 'rust-sailfish/sailfish'
-repo_url: 'https://github.com/rust-sailfish/sailfish'
+repo_name: "rust-sailfish/sailfish"
+repo_url: "https://github.com/rust-sailfish/sailfish"
 
-# Configuration
 theme:
-  name: 'material'
-  language: 'en'
-  logo: 'images/logo.svg'
+  name: "material"
+  language: "en"
+  logo: "images/logo.svg"
   palette:
-    scheme: 'default'
-    primary: 'deep purple'
-    accent: 'deep purple'
-  favicon: 'images/favicon.ico'
+    - media: "(prefers-color-scheme: dark)"
+      scheme: "dark"
+      primary: "deep purple"
+      accent: "deep purple"
+      toggle:
+        icon: "material/lightbulb-outline"
+        name: "Light Mode"
+    - media: "(prefers-color-scheme: light)"
+      scheme: "default"
+      primary: "deep purple"
+      accent: "deep purple"
+      toggle:
+        icon: "material/lightbulb"
+        name: "Dark Mode"
+  favicon: "images/favicon.ico"
   font:
-    text: 'Ubuntu'
-    code: 'Ubuntu Mono'
+    text: "Ubuntu"
+    code: "Ubuntu Mono"
   features:
-    - 'navigation.expand'
+    - "navigation.expand"
 
 # Extensions
 markdown_extensions:
-  - 'admonition'
-  - 'footnotes'
-  - 'pymdownx.highlight'
-  - 'pymdownx.tabbed'
-  - 'pymdownx.superfences':
+  - "admonition"
+  - "footnotes"
+  - "pymdownx.highlight"
+  - "pymdownx.tabbed":
+      alternate_style: true
+  - "pymdownx.superfences":
       custom_fences:
         - name: mermaid
           class: mermaid
 
 extra_css:
-  - 'assets/css/custom.css'
+  - "assets/css/custom.css"
 
 extra:
   social:
-    - icon: 'fontawesome/brands/github-alt'
-      link: 'https://github.com/rust-sailfish'
+    - icon: "fontawesome/brands/github-alt"
+      link: "https://github.com/rust-sailfish"
 
 # Page tree
 nav:
-  - 'Welcome': 'index.md'
-  - 'Installation': 'installation.md'
-  - 'Getting Started': 'getting-started.md'
-  - 'Configuration': 'options.md'
-  - 'Syntax':
-    - 'Overview': 'syntax/overview.md'
-    - 'Tags': 'syntax/tags.md'
-    - 'Includes': 'syntax/includes.md'
-    - 'Filters': 'syntax/filters.md'
+  - "Welcome": "index.md"
+  - "Installation": "installation.md"
+  - "Getting Started": "getting-started.md"
+  - "Configuration": "options.md"
+  - "Syntax":
+      - "Overview": "syntax/overview.md"
+      - "Tags": "syntax/tags.md"
+      - "Includes": "syntax/includes.md"
+      - "Filters": "syntax/filters.md"
diff --git a/requirements.txt b/requirements.txt
index f6798a40..5215838b 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -1,2 +1,2 @@
-mkdocs-material==5.2.3
+mkdocs-material==8.2.3
 mkdocs==1.2.3