resources.ToCSS

resources.ToCSS [OPTIONS] RESOURCE

resource.Resource

toCSS

{{ with resources.Get "sass/main.scss" }}
  {{ $opts := dict "transpiler" "libsass" "targetPath" "css/style.css" }}
  {{ with . | toCSS $opts }}
    {{ if hugo.IsDevelopment }}
      <link rel="stylesheet" href="{{ .RelPermalink }}">
    {{ else }}
      {{ with . | minify | fingerprint }}
        <link rel="stylesheet" href="{{ .RelPermalink }}" integrity="{{ .Data.Integrity }}" crossorigin="anonymous">
      {{ end }}
    {{ end }}
  {{ end }}
{{ end }}

Transpile Sass to CSS using the LibSass transpiler included in Hugo’s extended edition, or install Dart Sass to use the latest features of the Sass language.

Sass has two forms of syntax: SCSS and indented. Hugo supports both.

Options

transpiler

(string) The transpiler to use, either libsass (default) or dartsass. Hugo’s extended edition includes the LibSass transpiler. To use the Dart Sass transpiler, see the installation instructions below.

targetPath

(string) If not set, the transformed resource’s target path will be the original path of the asset file with its extension replaced by .css.

vars

(map) A map of key/value pairs that will be available in the hugo:vars namespace. Useful for initializing Sass variables from Hugo templates.

// LibSass
@import "hugo:vars";

// Dart Sass
@use "hugo:vars" as v;

outputStyle

(string) Output styles available to LibSass include nested (default), expanded, compact, and compressed. Output styles available to Dart Sass include expanded (default) and compressed.

precision

(int) Precision of floating point math. Not applicable to Dart Sass.

enableSourceMap

(bool) If true, generates a source map.

sourceMapIncludeSources

(bool) If true, embeds sources in the generated source map. Not applicable to LibSass.

includePaths

(slice) A slice of paths, relative to the project root, that the transpiler will use when resolving @use and @import statements.

{{ $opts := dict
  "transpiler" "dartsass"
  "targetPath" "css/style.css"
  "vars" site.Params.styles
  "enableSourceMap" (not hugo.IsProduction) 
  "includePaths" (slice "node_modules/bootstrap/scss")
}}
{{ with resources.Get "sass/main.scss" | toCSS $opts | minify | fingerprint }}
  <link rel="stylesheet" href="{{ .RelPermalink }}" integrity="{{ .Data.Integrity }}" crossorigin="anonymous">
{{ end }}

Dart Sass

The extended version of Hugo includes LibSass to transpile Sass to CSS. In 2020, the Sass team deprecated LibSass in favor of Dart Sass.

Use the latest features of the Sass language by installing Dart Sass in your development and production environments.

Installation overview

Dart Sass is compatible with Hugo v0.114.0 and later.

If you have been using Embedded Dart Sass¹ with Hugo v0.113.0 and earlier, uninstall Embedded Dart Sass, then install Dart Sass. If you have installed both, Hugo will use Dart Sass.

If you install Hugo as a Snap package there is no need to install Dart Sass. The Hugo Snap package includes Dart Sass.

Installing in a development environment

When you install Dart Sass somewhere in your PATH, Hugo will find it.

You may also install prebuilt binaries for Linux, macOS, and Windows.

Run hugo env to list the active transpilers.

Installing in a production environment

For CI/CD deployments (e.g., GitHub Pages, GitLab Pages, Netlify, etc.) you must edit the workflow to install Dart Sass before Hugo builds the site². Some providers allow you to use one of the package managers above, or you can download and extract one of the prebuilt binaries.

GitHub Pages

To install Dart Sass for your builds on GitHub Pages, add this step to the GitHub Pages workflow file:

- name: Install Dart Sass
  run: sudo snap install dart-sass

If you are using GitHub Pages for the first time with your repository, GitHub provides a starter workflow for Hugo that includes Dart Sass. This is the simplest way to get started.

GitLab Pages

To install Dart Sass for your builds on GitLab Pages, the .gitlab-ci.yml file should look something like this:

variables:
  HUGO_VERSION: 0.122.0
  DART_SASS_VERSION: 1.70.0
  GIT_DEPTH: 0
  GIT_STRATEGY: clone
  GIT_SUBMODULE_STRATEGY: recursive
  TZ: America/Los_Angeles
image:
  name: golang:1.20-buster
pages:
  script:
    # Install Dart Sass
    - curl -LJO https://github.com/sass/dart-sass/releases/download/${DART_SASS_VERSION}/dart-sass-${DART_SASS_VERSION}-linux-x64.tar.gz
    - tar -xf dart-sass-${DART_SASS_VERSION}-linux-x64.tar.gz
    - cp -r dart-sass/* /usr/local/bin
    - rm -rf dart-sass*
    # Install Hugo
    - curl -LJO https://github.com/gohugoio/hugo/releases/download/v${HUGO_VERSION}/hugo_extended_${HUGO_VERSION}_linux-amd64.deb
    - apt install -y ./hugo_extended_${HUGO_VERSION}_linux-amd64.deb
    - rm hugo_extended_${HUGO_VERSION}_linux-amd64.deb
    # Build
    - hugo --gc --minify
  artifacts:
    paths:
      - public
  rules:
    - if: $CI_COMMIT_BRANCH == $CI_DEFAULT_BRANCH

Netlify

To install Dart Sass for your builds on Netlify, the netlify.toml file should look something like this:

[build.environment]
HUGO_VERSION = "0.122.0"
DART_SASS_VERSION = "1.70.0"
TZ = "America/Los_Angeles"

[build]
publish = "public"
command = """\
  curl -LJO https://github.com/sass/dart-sass/releases/download/${DART_SASS_VERSION}/dart-sass-${DART_SASS_VERSION}-linux-x64.tar.gz && \
  tar -xf dart-sass-${DART_SASS_VERSION}-linux-x64.tar.gz && \
  rm dart-sass-${DART_SASS_VERSION}-linux-x64.tar.gz && \
  export PATH=/opt/build/repo/dart-sass:$PATH && \
  hugo --gc --minify \
  """

Example

To transpile with Dart Sass, set transpiler to dartsass in the options map passed to resources.ToCSS. For example:

{{ with resources.Get "sass/main.scss" }}
  {{ $opts := dict "transpiler" "dartsass" "targetPath" "css/style.css" }}
  {{ with . | toCSS $opts }}
    {{ if hugo.IsDevelopment }}
      <link rel="stylesheet" href="{{ .RelPermalink }}">
    {{ else }}
      {{ with . | minify | fingerprint }}
        <link rel="stylesheet" href="{{ .RelPermalink }}" integrity="{{ .Data.Integrity }}" crossorigin="anonymous">
      {{ end }}
    {{ end }}
  {{ end }}
{{ end }}

Miscellaneous

If you build Hugo from source and run mage test -v, the test will fail if you install Dart Sass as a Snap package. This is due to the Snap package’s strict confinement model.