Generated by SassMeister.com, the Sass playground.

SassMeister-input.scss

// Sass v3.2.7

h2 {
    div {
        color: red;
        
        .sub & {
            color: blue;
        }
    }
}

$color: orange;

h3 {
    color: complement($color);
}

%shadow {
    box-shadow: 2px 2px 10px black;
}

.element {
    color: red;
    height: 20px;
    @extend %shadow;
}

.element2 {
    color: blue;
    @extend %shadow;
}

$rem: 16;

@mixin rem($property, $value: '', $value2: '', $value3: '', $value4: '', $add: '') {
    @if $value2 == "" {
        #{$property}: $value * $rem#{px};
        #{$property}: $value#{rem};
    } @else if $value3 == "" {
        #{$property}: $value * $rem#{px} $value2 * $rem#{px};
        #{$property}: $value#{rem} $value2#{rem};
    } @else if $value4 == "" {
        #{$property}: $value * $rem#{px} $value2 * $rem#{px} $value3 * $rem#{px};
        #{$property}: $value#{rem} $value2#{rem} $value3#{rem};
    } @else {
        #{$property}: $value * $rem#{px} $value2 * $rem#{px} $value3 * $rem#{px} $value4 * $rem#{px} #{$add};
        #{$property}: $value#{rem} $value2#{rem} $value3#{rem} $value4#{rem} #{$add};
    }
}

.element3 {
    @include rem(height, 2);
    @include rem(margin, 2, 4);
    @include rem(padding, 2, 4, 6);
    @include rem(padding, 2, 4, 6, 8);
    @include rem(box-shadow, .2, .2, 0, 1, rgba(255,255,0,.4));
}

$color2: red;
$color3: rgba(255,255,100,.4);

.element4 {
    color: rgba(#ededed, .25);
    color: transparentize($color3,.1);
}

SassMeister-output.css

h2 div {
  color: red;
}
.sub h2 div {
  color: blue;
}

h3 {
  color: #005aff;
}

.element, .element2 {
  box-shadow: 2px 2px 10px black;
}

.element {
  color: red;
  height: 20px;
}

.element2 {
  color: blue;
}

.element3 {
  height: 32px;
  height: 2rem;
  margin: 32px 64px;
  margin: 2rem 4rem;
  padding: 32px 64px 96px;
  padding: 2rem 4rem 6rem;
  padding: 32px 64px 96px 128px ;
  padding: 2rem 4rem 6rem 8rem ;
  box-shadow: 3.2px 3.2px 0px 16px rgba(255, 255, 0, 0.4);
  box-shadow: 0.2rem 0.2rem 0rem 1rem rgba(255, 255, 0, 0.4);
}

.element4 {
  color: rgba(237, 237, 237, 0.25);
  color: rgba(255, 255, 100, 0.3);
}