This output format is built with bootstrap, using carefully craft features to provide a clean reading experience whether your on a phone, tablet, or desktop.

Some of the main features:

  • Easy customisation of colours and fonts with bslib

  • Built in search (broken down by section) that helps you quickly find what you're looking for.

  • A sidebar containing a within-chapter table of contents that makes navigation easy and helps provide context about your current position within the chapter.

  • Thoughtful typography to make the contents as easy as possible to read, regardless of the size of your device. A sticky header gets out of your way when reading, but is easily accessible if you need it.

  • In-line footnotes mean you can read asides next to the next they refer to. This theme is best paired with a reference style that generates footnotes.

  • R syntax highlighting and autolinking by downlit is paired with a accessible colour scheme designed by Alison Hill.

This theme is designed for books that use one chapter per page.

  theme = bs4_book_theme(),
  repo = NULL,
  lib_dir = "libs",
  pandoc_args = NULL,
  extra_dependencies = NULL

bs4_book_theme(primary = "#0068D9", ...)



A named list or bslib::bs_theme() object. The default, bs4_book_theme(), resets the base font size to 1rem to make reading easier and uses a primary colour with greater constrast against the background.


Link to repository where book is hosted, used to generate view source and edit buttons. Currently assumes GitHub and that the book is in the root directory of the repo.

lib_dir, pandoc_args, extra_dependencies, ...

Passed on to rmarkdown::html_document().


Primary colour: used for links and background of footer.