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Customise your site

This vignette teaches you how to customise the style/design of your pkgdown site. We’ll start by discussing two techniques that only require tweaks to your _pkgdown.yml: theming (colours and fonts) and layout (content of the navbar, sidebar, footer, …). We’ll then discuss how to add additional HTML and other files. Next, we’ll discuss how to give multiple sites the same style using a package, then finish up with some workflow advice.

In terms of your _pkgdown.yml, this vignette focusses on the most important fields nested under template and navbar. To learn more about customising other aspects of the site, see the documentation for the indiviudal functions like build_reference(), build_articles(), build_home(), build_redirects(), and init_site(). To learn about less important fields nested under template, see build_site().

library(pkgdown)

Getting started

Most theming features work only with Bootstrap 5, so first update your site by adding the following lines to your _pkgdown.yml:

template:
  bootstrap: 5

Overall, the site should look pretty similar, but you will notice a number of small improvements. Most importantly, the default font is much bigger, making it considerably easier to read. Upgrading to Bootstrap 5 has a low chance of breaking your site unless you were using your own pkgdown templates or custom CSS.

Theming

There are two ways to change the visual style of your site from _pkgdown.yml: using a pre-packaged bootswatch theme or customising theme variables with bslib. The following sections show you how.

Please note that pkgdown’s default theme has been carefully optimised to be accessible, so if you make changes, make sure to also read vignette("accessibility") to learn about potential accessibility pitfalls.

Light switch

You can provide a “light switch” to allow your users to switch between dark and light themes by setting the light-switch template option to true:

template:
  light-switch: true

This will add a lightswitch component to the navbar, which by default appears at the far right. This allows the user to select light mode, dark mode, or auto mode (which follows the system setting). The modes are applied using Bootstrap 5.3’s colours modes so are not separate themes, but a thin layer of colour customisation applied via CSS.

Bootswatch themes

The easiest way to change the entire appearance of your website is to use a Bootswatch theme:

template:
  bootstrap: 5
  bootswatch: materia

(Themes are unlikely to work with the light switch, but you can try it and see.)

Changing the bootswatch theme affects both the HTML (via the navbar, more on that below) and the CSS, so you’ll need to re-build your complete site with build_site() to fully appreciate the changes. While you’re experimenting, you can speed things up by just rebuilding the home page and the CSS by running build_home_index(); init_site() (and then refreshing the browser).

Bootswatch templates with tall navbars (e.g. lux, pulse) also require that you set the pkgdown-nav-height bslib variable. Because Bootswatch themes are provided by the bslib R package, you can also nest the bootswatch field under the bslib field.

template:
  bootstrap: 5
  bslib:
    bootswatch: lux
    pkgdown-nav-height: 100px

You can find the correct height by running $(".navbar").outerHeight() in the javascript console.

bslib variables

Instead of picking a complete theme, you can tweak fonts and colours individually using bslib variables. bslib is an R package that wraps sass, the tool that Boostrap uses to produce CSS from a special language called scss. The primary advantage of scss over CSS is that it’s more programmable, so you can have a few key bslib variables that affect appearance of many HTML elements.

There are three key variables that affect the colour:

template:
  bootstrap: 5
  bslib:
    bg: "#202123"
    fg: "#B8BCC2"
    primary: "#306cc9"

You can customise other components by setting more specific bslib variables, taking advantage of inheritance where possible. For example, table-border-color defaults to border-color which defaults to gray-300. If you want to change the colour of all borders, you can set border-color and if you just want to change the colour of table borders, you can set table-border-color. You can find a full list of variables in the bslib docs.

If you’re using the light switch, many colours are available for customisation specifically for the dark theme.

Theming with bslib is powered by bslib::bs_theme() and the bslib field is a direct translation of the arguments to that function. As a result, you can fully specify a bslib theme using the template.bslib field, making it easy to share YAML with the output.html_document.theme field of an R Markdown document.

template:
  bslib:
    version: 5
    bg: "#202123"
    fg: "#B8BCC2"
    primary: "#306cc9"

While iterating on colours and other variables you only need to rerun init_site() and refresh your browser to see the changes.

Fonts

You can also override the default fonts used for the majority of the text (base_font), for headings (heading_font) and for code (code_font). The easiest way is to supply the name of a Google font with the following syntax:

template:
  bootstrap: 5
  bslib:
    base_font: {google: "Roboto"}
    heading_font: {google: "Roboto Slab"}
    code_font: {google: "JetBrains Mono"}

If you want to use a non-Google font, you’ll need to do a bit more work. There are two steps: you need to first configure the font with CSS and then use it in your _pkgdown.yml. There are two ways you might get the CSS:

Then in _pkgdown.yml you can use the name of the font you just specified:

template:
  bslib:
    base_font: proxima-nova

Depending on where the font is from (and if you purchased it), you may need to take additional steps to ensure that it can only be used from your site, and/or make sure that it can still be used when you’re previewing locally. If you’re having problems getting a custom font to work, looking for errors in the browser developer console is a good place to start.

When iterating on fonts, you’ll need to run build_home_index(); init_site() then refresh your browser to see the update.

Syntax highlighting

The colours used for syntax highlighting in code blocks are controlled by the theme setting:

template:
  bootstrap: 5
  theme: breeze-light

You can choose from any of the following options: a11y-dark, a11y-light, arrow-dark, arrow-light, atom-one-dark, atom-one-light, ayu-dark, ayu-light, ayu-mirage, breeze-dark, breeze-light, breezedark, dracula, espresso, github-dark, github-light, gruvbox-dark, gruvbox-light, haddock, kate, monochrome-dark, monochrome-light, monochrome, monokai, nord, oblivion, printing, pygments, radical, solarized-dark, solarized-light, solarized, tango, vim-dark, zenburn.

Bootswatch themes with a dark background (e.g. cyborg, darkly, solar) will need a dark syntax highlighting theme, e.g. arrow-dark:

template:
  bootstrap: 5
  bootswatch: cyborg
  theme: arrow-dark

If you’re using the light switch, you will want to provide a theme and a theme-dark:

template:
  light-switch: true
  theme: gruvbox-light
  theme-dark: gruvbox-dark

The foreground and background colours used for inline code are controlled by code-color and code-bg bslib variables. If you want inline code to match code blocks, you’ll need to override the variables yourself, e.g.:

template: 
  bootstrap: 5
  theme: arrow-dark  
  bslib:
    code-bg: "#2b2b2b"

Math rendering

By default, pkgdown will render math using mathml. mathml is the official standard for rendering math on the web, and requires no additional javascript or css dependencies. However, browser support for complex math is not always that good, so if you are including complex equations in your documentation, you may want to switch to either katex or mathjax by using the template.math-rendering field:

template:
  math-rendering: katex

Layout

You can customise the contents of the navbar, footer, using the navbar and footer fields. See ?build_home for how to customise the sidebar on the homepage. They all use a similar structure that separately defines the overall structure and the individual components.

Additional HTML and files

If you need to include additional HTML, you can add it in the following locations:

template:
  includes:
    in_header: <!-- inserted at the end of the head -->
    before_body: <!-- inserted at the beginning of the body -->
    after_body: <!-- inserted at the end of the body -->
    before_title: <!-- inserted before the package title in the header ->
    before_navbar: <!-- inserted before the navbar links -->
    after_navbar: <!-- inserted after the navbar links -->

You can include additional files by putting them in the right place:

Use init_site() to update your rendered website after making changes to these files.

Template packages

To share a pkgdown style across several packages, the best workflow is to create… a package! It can contain any of the following:

The pkgdown defaults will be overriden by these template files, which are in turn overridden by package specific settings.

Once you have created your template package theverybest, you need to set it as your site’s theme:

template:
  package: theverybest

You then also need to make sure it’s available when your site is built. Typically, you won’t want to publish this package to CRAN, but you will want to publish to GitHub. Once you’ve done that, and assuming you’re using the usethis workflow, add the following line to your DESCRIPTION:

Config/Needs/website: myorg/theverybest

This will ensure that the GitHub action will automatically install it from GitHub when building your pkgdown site.

To get some sense of how a theming package works, you can look at:

But please note that these templates aren’t suitable for use with your own package as they’re all designed to give a common visual identity to a specific family of packages.

Porting a template package

If you are updating a template package that works with pkgdown 1.0.0, create directories inst/pkgdown/BS5/templates and inst/pkgdown/BS5/assets (if you don’t have any templates/assets make sure to a add dummy file to ensure that git tracks them). The templates and assets directories directly under inst/pkgdown will be used by pkgdown 1.0.0 and by pkgdown 2.0.0 if boostrap: 3. The directories under inst/pkgdown/BS5/ will be used for pkgdown 2.0.0 with boostrap: 5. This lets your package support both versions of Bootstrap and pkgdown.

PR previews

Lastly, it might be useful for you to get a preview of the website in internal pull requests. For that, you could use Netlify and GitHub Actions (or apply a similar logic to your toolset):

Conclusion

In this vignette we explained how to change the theming and layout of pkgdown websites. Further work to improve user experience will involve:


  1. Note that dots (.) in the package name need to be replaced by hyphens (-) in the vignette filename to be recognized as the intro. That means for a package foo.bar the intro needs to be named foo-bar.Rmd.↩︎

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