Markdown
This theme uses Standard Markdown. There's no specifications or any custom configs given to Marked.js, but there is a couple of JavaScript programs that enhance the final result of Markdown to HTML compilation.
Code
An extensive syntax highlighting comes with this theme made possible by Highlight.js. If you would like to use a different stylesheet for Highlight.js or if you want to use a different Syntax Highlighting program, check out Advanced.
Emojis
Who doesn't :heart: emojis? Better yet, :github: style emojis. If your familiar with Github's Emoji Markup you can get started by including the markup in your Markdown files. Check out Ezmoji for more details.
Icons
The icon library included with this theme is Fontawesome. Icons can be used in your Markdown files, or directly in the output HTML.
If you want more customization, check out Advanced.