How would I add CSS classes to Pandoc Block nodes?

[solomon-b]

Im using Pandoc as a library in the backend of a website where I want to take markdown documents and render them as HTML. I"m using TailwindCSS for styling which means that I need to be able to add a custom CSS classes to the generated HTML elements.

Some of the Block constructors contain a Attr parameter which allows me to insert a class attribute via a recursive function. However, this is not the case for all Block constructors. Why is that? Is there some other way to insert attributes, either into the Pandoc AST or via the HTML writer?

[massifrg]

You can use Div elements around the blocks without Attr that you want to customize.

Div elements with a custom-style attribute are used, for example, to add custom styles to the paragraphs they enclose (only in some output formats, like DOCX, ICML, ODT).

::: {custom-style="myStyle"}
A paragraph.

Another paragraph.
:::

In this example, you get two paragraphs with "myStyle" custom style.

You can do something similar, but you must write a filter that uses that information to add classes to the HTML elements inside those Divs, when you convert from markdown to HTML.