The sass R package provides bindings to LibSass, a fast Sass compiler written in C++. Sass is a mature and stable CSS extension language that makes styling modern websites less complex and more composable.

Install the released version of sass from CRAN:

install.packages("sass")

Install the latest development build from GitHub:

# install.packages("remotes")
remotes::install_github("rstudio/sass")

To compile Sass into CSS, provide Sass to the input argument of the sass() function. input can be any of the following:

• An R string (as in the example below).
• A named list() defining Sass variables.
• A sass_file(), sass_import(), or sass_layer().
• A nested list() comprising of all the above.

library(sass)
sass(input = "
  $size: 50%;
  foo { margin: $size * .33; }
")

See sass’s overview vignette as well as the official Sass documentation.

If you have a question about sass, try asking one on https://forum.posit.co: