How to change the size of inline pdf in Pandoc generated html files?

I'm using [Pandoc](https://pandoc.org/MANUAL.html) to convert my mardown files to html files, html pages which are Github styled using [Github.html5](https://github.com/tajmone/pandoc-goodies/blob/master/templates/html5/github/GitHub.html5) from the [Pandoc-goodies](https://github.com/tajmone/pandoc-goodies) repo which is based on this other [repo](https://github.com/sindresorhus/github-markdown-css) . I'm extremely pleased to see that ![](./file.pdf) inserts the complete inline pdf in the html file output, however it's more or less at the minimal size, making it impossible to really read the pdf. How to tell Pandoc to resize this inline pdf ? I've tried the