I am using RStudio 1.1.463 on macOS 10.13.6 (17G65).
I have tried the syntax on this post
title: "R Notebook"
but the toc didn't show up.
adding css as follow
pandoc: Could not fetch /.../.../my.css
/.../.../my.css: openBinaryFile: does not exist (No such file or directory)
How to add table of contents in R notebook?