Generated by SassMeister.com.

SassMeister-input.scss

// ----
// libsass (v3.3.6)
// ----

// Small mixin
@mixin small-version {
  @at-root .small#{&} {
    @content;
  }
}

.bookshelf {
  color: brown;
  height: 100px;
  @include small-version {
    height: 50px;
  }

  .panel {
    trimmed: no;
    height: 10px;
    @include small-version {
      height: 5px;
    }
  }

  .door {
    height: 100px;
    @include small-version {
      height: 50px;
    }

    .knob {
      shape: circle;
      height: 10px;
      @include small-version {
        height: 5px;
      }
    }
  }
}

SassMeister-output.css

.bookshelf {
  color: brown;
  height: 100px;
}

.small.bookshelf {
  height: 50px;
}

.bookshelf .panel {
  trimmed: no;
  height: 10px;
}

.small.bookshelf .panel {
  height: 5px;
}

.bookshelf .door {
  height: 100px;
}

.small.bookshelf .door {
  height: 50px;
}

.bookshelf .door .knob {
  shape: circle;
  height: 10px;
}

.small.bookshelf .door .knob {
  height: 5px;
}