Rule Inheritance

By using the @extend directive and passing it a named ruleset or selector from any other rule you can share styles more effectively across a stylesheet.

Abstract rules can be used if you just need to extend a generic set of declarations.

.negative-text {
  overflow: hidden;
  text-indent: -9999px;
}

.sidebar-headline {
  @extend .negative-text;
  background: url( headline.png ) no-repeat;
}

Renders as

.negative-text,
.sidebar-headline {
  overflow: hidden;
  text-indent: -9999px;
}

.sidebar-headline {
  background: url( headline.png ) no-repeat;
}

Referencing by name

If you want to reference a rule without being concerned about later changes to the identifying selector use the @name directive:

.renamedClass {
  @name baseClass;
  text-decoration: underline;
}

.myClass {
  @extend baseClass;
}

Extending with pseudo classes/elements

@extend arguments can adopt pseudo classes/elements by appending an exclamation mark:

.link-base {
  color: #bada55;
  text-decoration: underline;
}
.link-base:hover,
.link-base:focus {
  text-decoration: none;
}

.link-footer {
  @extend .link-base, .link-base:hover!, .link-base:focus!;
  color: blue;
}

Renderd as

.link-base,
.link-footer {
  color: #bada55;
  text-decoration: underline;
}

.link-base:hover,
.link-base:focus,
.link-footer:hover,
.link-footer:focus {
  text-decoration: none;
}

.link-footer {
  color: blue;
}