I have Pandoc v1.17.0.4.

My very first markdown file, 00intro.md, includes this YAML block:
---
title: My title
author:
- My author
date: Various dates
---

I turn Markdown files into EPUB files using this command line in the Windows cmd window:
c:\chuck\ebook\pandoc\pandoc -f markdown_mmd+backtick_code_blocks+yaml_metadata_block -t epub -o %outfile% --toc --css=style01.css 00intro.md 01.md

After I create the epub I copy the epub to a zip file and look inside.
The XHTML files reference "stylesheet.css" first (which is ok), then immediately below that they reference my custom css file "style01.css". "stylesheet.css" is in the root dir of the zip file, but "style01.css" is not in the EPUB file.

Is this a bug? Or do I have to specify "style01.css" in a different way? Perhaps in my YAML block?

Thanks.