DRY CSS output using Sass

dry-css-with-sass.scss

/**
 Placeholder - Contains all static mixin name value pairs for a particular mixin
*/
%box {
  border: 1px solid;
  padding: 1em;
  margin: 1em;
}

/**
 Mixin - Contains the dynamic user-provided variables only 
*/
@mixin module($bgcolor, $border) {
  background-color: $bgcolor;
  border-color: $border;
  @extend %box;
}

/** 
 End Result: DRY CSS
 */
.thisbox {
  @include module(Tomato, #888);
}
.thatbox {
  @include module(slategray, Tomato);
  color: white;
}
.anotherbox {
  @include module(beige, green);
}