HTML option to make the table of contents (right margin) "floating" like for the left sidebar

[allefeld]

Description

For the left sidebar, which lists different documents in a website project, there is an option style: floating, which hides the sidebar if there is not enough space for it, and includes a button to show it on top of the page content.

My feature request is to enable the same for the right margin which by default contains the table of contents, e.g. as an option toc-style: floating or toc-floating: true.

The reason is that when I work on a document in VS Code with the markdown and preview side by side, including the table of contents makes the main contents too narrow, especially for computational documents with code which I write to the standard line length of 80 characters. At the same time, if the document gets long, navigation through the table of contents is essential.

I searched for this feature and found several sites (e.g. r4ds) claiming that there is a Quarto option toc_float, however that seems to be outdated or just plain false. Moreover, I suspect floating in this context means something else, namely that the table of contents is pinned to the top of the viewport.