consistent parameter passing for html and latex-generated pdf

[phaustin]

@hcolclou and I have pushed a new sphinx theme that implements some CSS3 page media formatting for myst_nb:
https://github.com/eoas-ubc/paged_html_theme#pagedjs-html-sphinx-theme

We'll be using it to provide parts of the functionality of the latex geometry, fancyhdrs, Lastpage packages as well as an explicit pagebreak.

@choldgraf and @chrisjsewell -- any thoughts on the best way to pass mulitple parameters like margin/header sizes/content so that the same format works for both latex and chrome-pdf builders? Tagging @racooneer since it's related to jupyter-book/jupyter-book#653

[mmcky]

this is an important issue. thanks for opening @phaustin. I think the best approach (but time consuming) is to start building a spec of the parameters that we want to start supporting with a column for myst option -> desired html, pdfhtml and pdflatex output.

This will allow the different teams to work to a single spec and reserve option names when implementing support for the metadata that has been specified in myst in a consistent manner?

Alternatively we could setup an issue template for myst option and I can sync those across to a document for reference. My only hesitation is some options are discussed in myst-parser and others in myst-nb and others in jupyter-book.

Not sure where to put this (@choldgraf)? -- should we have a myst-specification repo? I was thinking the docs for myst-parser given it holds much of the myst specification - but not always obvious for others to review. It needs to be in a place everyone can refer to and is easily accessible / editable.

[choldgraf]

I think it's worth having a spec. Right now the myst-parser serves as a reference implementation but I don't know that we have a really clear pattern others can follow for expected behavior.