Problem with styling (only default style works)

Thanks for making this useful plugin!

I am having a problem: everything seems to work with HTML generation, but the HTML is rendered with no styling.

None of the options under "Pick a markdown and code style:" seem to have any effect with the exception of "default" which does apply a basic style.

The .md file is local on my machine. I am using firefox on a macbook (all fully updated).

Any recommendations for fixing or troubleshooting?

Start by reproducing the problem in Firefox on macOS with a local .md file, comparing the default style with each option under “Pick a markdown and code style:”. Trace how the selected style is applied to the generated HTML. Done means every supported non-default style visibly affects the rendered document, or the unsupported options are clearly identified.

Written by the indexing model from the issue text.