markdown-pdf

https://github.com/hanggrian/markdown-pdf-styles/tree/main

samples includes css

.vscode/setting.json

{
  "markdown-pdf.styles": ["./markdown-pdf.css"]
}

markdown-pdf.css mix css

online markdown editor

https://stackedit.io/

https://github.com/lepture/editor

markdown

Finaly
use  

• ruby gem  "redcarpet"

then  online edit

• https://stackedit.io/

css file

• <link rel="stylesheet" href="https://stackedit.io/res-min/themes/base.css">

use on website
https://github.com/chjj/marked/
http://strapdownjs.com/

https://github.com/showdownjs/showdown
https://github.com/showdownjs/showdown/tree/master/compressed
https://github.com/showdownjs/showdown/tree/master/compressed/extensions

https://code.google.com/p/pagedown/wiki/PageDown
https://code.google.com/p/pagedown/source/browse/

online editor
http://daringfireball.net/projects/markdown/
http://daringfireball.net/projects/markdown/dingus

online editor
https://stackedit.io/
https://stackedit.io/editor#


http://strapdownjs.com/

https://github.com/evilstreak/markdown-js
http://markdownlivepreview.com/

http://www.codingdrama.com/bootstrap-markdown/

http://demo.neutrinoboy.jp/jquery-markdown/