For my novel, I wanted to have a different style for conversations (or events) that are happening simultaneously. And I wanted to use Markdown. Rather than sprinkling TeX commands throughout the document, I use annotations, which were introduced by pandoc. Annotations resemble:

    ::: {.concurrent title="Hacker News Thread 1"}
    I'm writing in an HN thread.
    :::

    ::: {.concurrent title="Hacker News Thread 2"}
    This is a separate thread.
    :::

This gets styled in the PDF as:

https://i.ibb.co/ZfZXmDn/output.png

Later, I could opt to format the concurrent threads as two-column text ... without changing the Markdown source file.

Various styles are packed in themes, which the user can select when exporting to PDF. At present, there are only three themes:

https://github.com/DaveJarvis/keenwrite-themes/tree/main/exa...

There other styles in the Boschet theme, such as speech bubbles, TODOs, and so forth:

    ::: bubbletx
    Speech sent from the device.
    :::

    ::: bubblerx
    Speech received by the device.
    :::

Here's a video showing how they appear in the preview window:

https://youtu.be/7icc4oZB2I4?list=PLB-WIt1cZYLm1MMx2FBG9KWzP...

Creating a theme for tabletop role-playing games would take some elbow grease. When finished, it'd mean people could write their documents in Markdown and reuse the same theme, without having to know how TeX commands work. Knowing TeX commands is a barrier to entry for a lot of people.