Add ScalaCSS to your project by adding this dependency to your SBT build:
libraryDependencies += "com.github.japgolly.scalacss" %% "core" % "0.8.0-RC1"
Or for Scala.JS:
libraryDependencies += "com.github.japgolly.scalacss" %%% "core" % "0.8.0-RC1"
Then to start using it, decide which of the following best suits your needs.
StyleSheets come in two flavours.
Produces static CSS for external consumption.
Like SCSS and LESS.
Styles are values that can be applied directly in Scala & Scala.JS to HTML-like stuff.