_output.yml

bookdown::gitbook:
  split_by: section
  config:
    toc:
      collapse: subsection
      before: |
        <li><strong><a href="./">R Graphics Cookbook</a></strong></li>
    edit:
      link: https://github.com/wch/rgcookbook/edit/master/%s
      text: "Edit"
    sharing:
      facebook: no
      twitter: no
      github: yes
      all: []

bookdown::pdf_book:
  toc_depth: 2