Generated by SassMeister.com.

SassMeister-input.scss

// ----
// Sass (v3.3.14)
// Compass (v1.0.1)
// ----

@mixin attention($self: false) {
    @if($self != false) {
        &,
        &:hover,
        &:active,
        &:focus {
            @content;
        }
    }

    @else {
        &:hover,
        &:active,
        &:focus {
            @content;
        }
    }
}

// Generate Helvetica Neue’s numbered font-weights from their aliases.
@mixin font-weight($font-weight) {

    @if ($font-weight == "regular") {
        font-weight: 300;
    }

    @if ($font-weight == "bold") {
        font-weight: 600;
    }

}

@mixin headings($from: 1, $to: 6) {
    %base-heading {
        @content;
    }

    @if $from >= 1 and $to <= 6{
        @for $i from $from through $to{
            h#{$i} {
                @extend %base-heading;
            }
        }
    }
}

// ---------------------------------------------------------------

@include headings() {
  @include font-weight(regular);
  color: red;
}

.btn {
  @include font-weight(bold);

  @include attention() {
    background-color: blue; 
  }
}

.btn--positive {
  @include font-weight(regular);
  
  @include attention(self) {
    background-color: red;
  }
}

SassMeister-output.css

h1, h2, h3, h4, h5, h6 {
  font-weight: 300;
  color: red;
}

.btn {
  font-weight: 600;
}
.btn:hover, .btn:active, .btn:focus {
  background-color: blue;
}

.btn--positive {
  font-weight: 300;
}
.btn--positive, .btn--positive:hover, .btn--positive:active, .btn--positive:focus {
  background-color: red;
}