Generated by SassMeister.com.

SassMeister-input.scss

// ----
// Sass (v3.3.0.rc.4)
// Compass (v1.0.0.alpha.18)
// ----

// Start with a class .foo
%foo {
  line-height: 150%;
  font-size: 2em;
}

.foo {
  @extend %foo;
}

// Now @extend it
@mixin green-foo {
  @extend %foo;
  color: green;
}

// Use the mixin somewhere
.xxx .yyy {
  @include green-foo;
}

.www .zzz {
  @include green-foo;
}

.xyz .vwx {
  @include green-foo;
}

/*
Much better now!
*/

.abc .def .foo {
  color: red;
}

.some .selector .foo, .or .some .other .selector .foo {
  line-height: 2em;
}

.see .if .i .actually .style .foo .then .pretty .bad .things .happen {
  background: pink;
}

SassMeister-output.css

.foo, .xxx .yyy, .www .zzz, .xyz .vwx {
  line-height: 150%;
  font-size: 2em;
}

.xxx .yyy {
  color: green;
}

.www .zzz {
  color: green;
}

.xyz .vwx {
  color: green;
}

/*
Much better now!
*/
.abc .def .foo {
  color: red;
}

.some .selector .foo, .or .some .other .selector .foo {
  line-height: 2em;
}

.see .if .i .actually .style .foo .then .pretty .bad .things .happen {
  background: pink;
}