# Data : Markdown
\[ [CommonMark](https://spec.commonmark.org/0.30/) | [GitHub](https://github.github.com/gfm/) | [Obsidian](https://help.obsidian.md/Editing+and+formatting/) ]
###### Basics
- extension: `.md`, `.markdown`
- media type: `text/markdown`
- consecutive spaces are collapsed — use to force
- consecutive newlines are collapsed — use `<br>` to force
- HTML is mostly allowed — but not JavaScript
- use `\` to escape a character when necessary
- use `%%` to comment out a section
###### External Links
```md
[label](url-for-link) # must escape spaces with %20 or by wrapping url in <>
 # supports images, tweets, and youtube videos
```
###### Internal Links — Wikilinks
```md
[[note-to-link]] # only need note path if note name isn't unique
[[note-to-link#heading]]
[[note-to-link|label]]
![[note-to-embed]]
```
###### Internal Links — Markdown
```md
[label](note)
[label](file.ext) # extension required for non-Markdown files
```
###### Shortcut Reference Links
```md
[ref]
[ref]: url-for-link
```
###### Footnotes
Footnoted text will be decorated with a numbered superscript link to the footnote, which appears at the bottom of the page.
```md
footnoted text ^[inline footnote content]
footnoted text[^ref]
[^ref]: footnote content
```
###### Callouts
Creates a colored box with an icon and title, like "Info". Title can be customized. Body is optional and can contain arbitrary markup. Body is optionally foldable — add "+" or "-" after closing bracket.
```md
> [!style] optional custom title
> optional body containing arbitrary markdown
```
> [!info] Built-in styles (icon + title):
> *abstract, bug, danger, example, failure, info, note, question, quote, tip, todo, success, warning*
###### Metadata aka Properties aka Frontmatter
A YAML document at the top of the Markdown document.
```md
---
property1: value1
...
---
...Markdown...
```