Getting downlit to work on notebook HTML

notestar, which I use to create project notebooks, produces an HTML file. I can then post-process this HTML file using downlit::downlit_html_path() so that R function calls are automatically linked to documentation pages. This feature is great, but out of the box, it ignores the syntax highlighting of the output document. The solution, it turns out, is buried in ?rmarkdown::html_document. I make sure that the following css file is included in the build process, so that links are underlined and the style defers to the default syntax highlighting coloring.

code a:any-link {
 color: inherit; /* use colour from syntax highlighting */
 text-decoration: underline;
 text-decoration-color: #ccc;
}