bookdown::gitbook:
  css: style.css
  toolbar:
      position: fixed
  config:
    toc:
      collapse: subsection
      before: |
        <li><a href="./">Authoring Books with R Markdown</a></li>
      after: |
        <li><a href="https://bookdown.org" target="blank">Published with bookdown</a></li>
    download: [pdf, epub]
bookdown::pdf_book:
  includes:
    in_header: latex/preamble.tex
    before_body: latex/before_body.tex
    after_body: latex/after_body.tex
  keep_tex: yes
  latex_engine: xelatex
  citation_package: natbib
  template: null
  pandoc_args: --chapters
bookdown::epub_book: 
  stylesheet: css/style.css

bookdown::gitbook:
  css: style.css
  toolbar:
      position: fixed
  config:
    toc:
      collapse: subsection
      before: |
        <li><a href="./">R Programming for Research</a></li>
      after: |
        <li><a href="https://bookdown.org" target="blank">Published with bookdown</a></li>
    download: [pdf, epub]
bookdown::pdf_book:
  includes:
    in_header: latex/preamble.tex
    before_body: latex/before_body.tex
    after_body: latex/after_body.tex
  keep_tex: yes
  latex_engine: xelatex
  citation_package: natbib
  template: null
  pandoc_args: --chapters
bookdown::epub_book: 
  stylesheet: css/style.css

Fix top left corner of webpage
Fix top left corner of webpage
