Callouts are an excellent way to draw extra attention to certain concepts, or to more clearly indicate that certain content is supplemental or applicable to only some scenarios.

Callout Types
There are five different types of callouts available.

note
warning
important
tip
caution

The color and icon will be different depending upon the type that you select. Here are what the various types look like in HTML output:






Note



Note that there are five types of callouts, including: note, tip, warning, caution, and important.








Warning



Callouts provide a simple way to attract attention, for example, to this warning.








This is Important



Danger, callouts will really improve your writing.








Tip With Title



This is an example of a callout with a title.








Expand To Learn About Collapse





This is an example of a ‘collapsed’ caution callout that can be expanded by the user. You can use collapse="true" to collapse it by default or collapse="false" to make a collapsible callout that is expanded by default.





Markdown Syntax
Create callouts in markdown using the following syntax (note that the first markdown heading used within the callout is used as the callout heading):
::: {.callout-note}
Note that there are five types of callouts, including:
`note`, `warning`, `important`, `tip`, and `caution`.
:::

::: {.callout-tip}
## Tip with Title

This is an example of a callout with a title.
:::

::: {.callout-caution collapse="true"}
## Expand To Learn About Collapse

This is an example of a 'folded' caution callout that can be expanded by the user. You can use `collapse="true"` to collapse it by default or `collapse="false"` to make a collapsible callout that is expanded by default.
:::
Note that above callout titles are defined by using a heading at the top of the callout. If you prefer, you can also specify the title using the title attribute. For example:
::: {.callout-tip title="Tip with Title"}
This is a callout with a title.
:::


Customizing Appearance

Collapse
You can create ‘folded’ callouts that can be expanded by the user by settings the collapse attribute on the callout. If you set collapse=true, the callout will be expandable, but will be collapsed by default. If you set collapse=false, the callout will be expanded, but will be expanded by default.


Appearance
Callouts have 3 different looks you can use.







default
The default appearance with colored header and an icon.


simple
A lighter weight appearance that doesn’t include a colored header background.


minimal
A minimal treatment that applies borders to the callout, but doesn’t include a header background color or icon.



You can set the callout appearance either globally in the document (or project yaml):
callout-appearance: simple
or by setting the type attribute on the callout. For example
::: {.callout-note appearance="simple"}

## Pay Attention

Using callouts is an effective way to highlight content that your reader give special consideration or attention.

:::
which appears as:






Pay Attention



Using callouts is an effective way to highlight content that your reader give special consideration or attention.




Icons
In addition to controlling the appearance of the callout, you can also choose to directly suppress the icon by setting the global option in your document (or project) yaml:
callout-icon: false
or by setting an attribute directly on the callout:
::: {.callout-note icon=false}

## Pay Attention

Using callouts is an effective way to highlight content that your reader give special consideration or attention.

:::
Which will appear as:






Pay Attention



Using callouts is an effective way to highlight content that your reader give special consideration or attention.





Format Support
The following formats render callouts as illustrated above:

HTML
PDF
MS Word
EPUB
revealjs

Note that callout rendering for HTML is not available when you disable the standard HTML theme (e.g. if you specify the theme: none option). Also, some features are specific to document using Bootstrap, like collapsible callouts, and won’t work in other documents.
When the target format doesn’t support callouts, they are rendered as a simple blockquote with the title in bold.