diff --git a/.prettierrc.yml b/.prettierrc.yml
new file mode 100644
index 0000000..2ce3586
--- /dev/null
+++ b/.prettierrc.yml
@@ -0,0 +1,3 @@
+# Disable formatting of quoted code embedded in a file because it breaks sample codes in the README.md.
+# https://prettier.io/docs/en/options.html#embedded-language-formatting
+embeddedLanguageFormatting: off
diff --git a/README.md b/README.md
index 1b59217..f81b029 100644
--- a/README.md
+++ b/README.md
@@ -2,23 +2,19 @@
 [![MIT License](https://img.shields.io/badge/license-MIT-blue.svg)](LICENSE)
 [![test](https://github.com/kg8m/vim-simple-align/actions/workflows/test.yml/badge.svg?branch=vim9)](https://github.com/kg8m/vim-simple-align/actions/workflows/test.yml?query=branch%3Avim9)
 
-
-vim-simple-align
-==================================================
+# vim-simple-align
 
 A Vim/Neovim plugin to align texts by simple way.
 
-* vim-simple-align provides only 1 command and a few its options
-  * no need to remember options because they can be completed
-* delimiter used to split texts is always Vim's regular expression
+- vim-simple-align provides only 1 command and a few its options
+  - no need to remember options because they can be completed
+- delimiter used to split texts is always Vim's regular expression
 
 vim-simple-align doesn't cover all alignment cases but aims to work nice in many common cases.
 
 https://user-images.githubusercontent.com/694547/119252181-beec6380-bbe5-11eb-87ce-4ed643598962.mp4
 
-
-Commands/Usage
---------------------------------------------------
+## Commands/Usage
 
 vim-simple-align provides only 1 command: `:SimpleAlign`.
 
@@ -38,7 +34,6 @@ Delimiter is Vim's regular expression. Some characters may need to be escaped.
 
 cf. `:h regular-expression`
 
-
 ### Options
 
 #### `-count` (`-c`) option
@@ -47,30 +42,25 @@ cf. `:h regular-expression`
 
 Default: `-1`
 
-
 #### `-lpadding` (`-l`) option
 
 `-lpadding` option means how many spaces to put left padding of each token. Available values are integers greater than or equal to 0.
 
 Default: `1`
 
-
 #### `-rpadding` (`-r`) option
 
 `-rpadding` option means how many spaces to put right padding of each token. Available values are integers greater than or equal to 0.
 
 Default: `1`
 
-
 #### `-justify` (`-j`) option
 
 `-justify` option means which side tokens should be on. Available values are `left` and `right`.
 
 Default: `left`
 
-
-Examples
---------------------------------------------------
+## Examples
 
 ### Align Markdown table
 
@@ -90,14 +80,12 @@ a | bbb | ccccc
 | .. | .. | .. |
 ```
 
-
 #### 🔧 Command
 
 ```vim
 :1,4SimpleAlign |
 ```
 
-
 #### ⭕️ Aligned
 
 ```md
@@ -114,7 +102,6 @@ a      | bbb | ccccc
 | ..     | ..  | ..    |
 ```
 
-
 ### Align Markdown table with justifying to right
 
 #### ❌ Not aligned
@@ -133,14 +120,12 @@ a | bbb | ccccc
 | .. | .. | .. |
 ```
 
-
 #### 🔧 Command
 
 ```vim
 :1,4SimpleAlign | -justify right
 ```
 
-
 #### ⭕️ Aligned
 
 ```md
@@ -157,7 +142,6 @@ a | bbb | ccccc
 |     .. |  .. |    .. |
 ```
 
-
 ### Align JSON, dictionary/hash items
 
 #### ❌ Not aligned
@@ -192,7 +176,6 @@ Ruby old Hash syntax:
 }
 ```
 
-
 #### 🔧 Command
 
 For JSON:
@@ -213,7 +196,6 @@ For Ruby old Hash syntax:
 :2,4SimpleAlign =>
 ```
 
-
 #### ⭕️ Aligned
 
 JSON:
@@ -246,7 +228,6 @@ Ruby old Hash syntax:
 }
 ```
 
-
 ### Align variable assignments
 
 #### ❌ Not aligned
@@ -275,7 +256,6 @@ a = "a"
 a += "a"
 ```
 
-
 #### 🔧 Command
 
 For basic case:
@@ -296,7 +276,6 @@ For `=` and `+=`:
 :1,2SimpleAlign [+\ ]=
 ```
 
-
 #### ⭕️ Aligned
 
 Basic case:
@@ -323,7 +302,6 @@ a  = "a"
 a += "a"
 ```
 
-
 ### Align output/result comments
 
 #### ❌ Not aligned
@@ -344,7 +322,6 @@ bbb #=> "bbb"
 ccccc #=> "ccccc"
 ```
 
-
 #### 🔧 Command
 
 For JavaScript:
@@ -359,7 +336,6 @@ For Ruby:
 :1,3SimpleAlign #=> -lpadding 2
 ```
 
-
 #### ⭕️ Aligned
 
 JavaScript:
@@ -378,7 +354,6 @@ bbb    #=> "bbb"
 ccccc  #=> "ccccc"
 ```
 
-
 ### Align non-whitespace characters
 
 #### ❌ Not aligned
@@ -390,14 +365,12 @@ t.boolean :active, null: false, default: true
 t.boolean :foo, null: true, default: false
 ```
 
-
 #### 🔧 Command
 
 ```vim
 :1,4SimpleAlign \S\+ -lpadding 0
 ```
 
-
 #### ⭕️ Aligned
 
 ```rb
@@ -407,21 +380,15 @@ t.boolean    :active, null: false, default: true
 t.boolean    :foo,    null: true,  default: false
 ```
 
+## Inspired by alignta
 
-Inspired by alignta
---------------------------------------------------
-
-vim-simple-align is inspired by [h1mesuke/vim-alignta](<https://github.com/h1mesuke/vim-alignta>). It is a simple Vim plugin to align texts. It provides only 1 command `:Alignta` and has a few options and command syntaxes. It is a very great plugin but doesn't work on current Vim. vim-simple-align inherits its philosophy and focuses its limited essential features.
-
+vim-simple-align is inspired by [h1mesuke/vim-alignta](https://github.com/h1mesuke/vim-alignta). It is a simple Vim plugin to align texts. It provides only 1 command `:Alignta` and has a few options and command syntaxes. It is a very great plugin but doesn't work on current Vim. vim-simple-align inherits its philosophy and focuses its limited essential features.
 
-Why not vim-easy-align?
---------------------------------------------------
+## Why not vim-easy-align?
 
 Yes, [vim-easy-align](https://github.com/junegunn/vim-easy-align) is a great Vim plugin. However, it is complicated and difficult for me. I can't remember its mappings, options, and syntaxes. It is a so cool product, but not for me.
 
-
-Installation
---------------------------------------------------
+## Installation
 
 If you use [dein.vim](https://github.com/Shougo/dein.vim):
 
@@ -431,9 +398,7 @@ call dein#add("kg8m/vim-simple-align")
 
 Note: dein.vim's lazy loading feature with `on_cmd` option is not recommended for vim-simple-align. You will see `E471: Argument required: ...` if so. To tell the truth, lazy loading of vim-simple-align doesn't make Vim's startup faster. On the one hand, vim-simple-align just defines 1 command when added to `runtimepath`. On the other hand, dein.vim's lazy loading with `on_cmd` also defines a dummy command.
 
-
-Vim9 script
---------------------------------------------------
+## Vim9 script
 
 You can use Vim9 script version if you use Vim 8.2.4053+. Vim9 script version is 5-10 times faster than legacy Vim script version. Vim9 script version is available on [`vim9` branch](https://github.com/kg8m/vim-simple-align/tree/vim9).
 
@@ -441,8 +406,6 @@ You can use Vim9 script version if you use Vim 8.2.4053+. Vim9 script version is
 call dein#add("kg8m/vim-simple-align", { "rev": "vim9" })
 ```
 
-
-Requirements
---------------------------------------------------
+## Requirements
 
 Vim 8.2+ or Neovim nightly