LaTex serif fonts not working on Pandoc

Question

I have some documents in markdown that I'm trying to convert to PDF using the default latex-engine, pdflatex. This is on a CentOS 7.9.

In the markdown minimal example file, I have a yaml header which is as follows

---
title: First Last
fontfamily: sans
...

Heading
=======

For converting, I'm using

pandoc --latex-engine=pdflatex README.md -o README.pdf

The above command works without producing any errors, however, the resulting PDF has the default serif font used by Pandoc's LaTeX (Latin Modern). I'm in no way able to change from Latin Modern Roman to Computer Modern Sans Serif. I'm a bit confused as to what settings I need in the yaml header to get the desired results.

Any help would be highly appreciated

Answer 1

The default template for Pandoc's interface through fontfamily requires a sty file to load the relevant font information from fd files (as in, say, mathpazo.sty, for instance: so you type fontfamily: mathpazo); and the default engine is already pdflatex, so you don't need to specify it as a flag in the CLI command. So, to achieve your results you may simply say

---
title: First Last
header-includes: \renewcommand*\familydefault{\sfdefault} 
...

Heading
=======

Use \renewcommand* as above to keep Roman available elsewhere, or \let\rmdefault\sfdefault instead of \renewcommand*\familydefault{\sfdefault} if you want to override completely the Roman font.

And for converting,

pandoc README.md -o README.pdf

Beware we are not setting up Computer Modern Sans Serif strictly, but the Latin Modern Sans Serif variant, which is the default for Pandoc. You may see the differences in another page of the Catalog

You may profit from retrieving the template for LaTeX output by typing pandoc -D latex and studying the output.