GitHub alerts html uses DOM structure deviating from GitHub.

[chrisgrieser]

A markdown file with these github-style alerts:

> [!Note]
> foobar

Using pandoc --from=gfm --to-html results in this HTML:

<div class="note">
<div class="title">
<p>Note</p>
</div>
<p>foobar</p>
</div>

However, on the GitHub website, that alert is rendered as:

<div class="markdown-alert markdown-alert-note">
<p class="markdown-alert-title">Note</p>
<p>foobar</p>
</div>

This is a problem, since common css files like github-markdown.css assume the latter HTML to style alerts correctly.

Also, the latter format makes more sense, and is more verbose in its use of more specific classes, so it would be preferable to use either way, imo.

Describe alternatives you've considered.
Manually rewrite the HTML generated by pandoc to match the GitHub one, OR rewrite the css file to target pandoc's HTML. But quite unconvenient.

Related issues

• Support for Github "Alerts" #10109
• Does anyone have a filter for alert / callout styling in PDF output? #9821

[jgm]

I'm not too inclined to change this. It's a matter of HTML rendering, rather than markdown parsing. Our aim is to correctly parse GFM; this doesn't necessarily include making all the same decisions about rendering the AST to HTML.

Rewriting the CSS doesn't seem like that big a task.

[chrisgrieser]

Our aim is to correctly parse GFM; this doesn't necessarily include making all the same decisions about rendering the AST to HTML.

I generally agree, but is there a particular reason for the html structure currently used by pandoc?

If it is an arbitrary decision or just a matter of taste, I don't see any reason why pandoc should not opt for the kind of output most compatible with other tools.

[jgm]

We need to parse this, not to HTML, but to pandoc's intermediate AST.
And that AST has no way to apply attributes directly to a Para element.