title: Using css variables in sass functions - node-sass
body: <p>I am trying to use CSS variables in an Angular project together with Sass functions (<code>lighten()</code> / <code>darken()</code> to be precise), and as far as I know, the latest version of LibSass allows it.  </p>
  
  <p>I have installed <code>node-sass@4.11.0</code> and <code>sass-loader@7.1.0</code> (and on Angular v7.3.0), but yet I receive an error </p>
  
  <blockquote>
    <p>Argument $color of lighten($color, $amount) must be a color</p>
  </blockquote>
  
  <p>Am I missing something?<br>
  Thanks! </p>