Generated by SassMeister.com.

SassMeister-input.scss

// ----
// libsass (v3.2.5)
// ----

//Variables
$default-font-color: red;
$default-width: 10px;
$title-font-color: blue;

//Mixins (functions)
@mixin formatTitle($font-size, $font-color, $font) {
  font: $font-size $font;
  color: $font-color;
}

h1 {
  @include formatTitle(12px, $title-font-color, Arial);
  
  span {
    color: $default-font-color;
    width: $default-width;
  }
}

SassMeister-output.css

h1 {
  font: 12px Arial;
  color: blue;
}

h1 span {
  color: red;
  width: 10px;
}