_bulletproof-clearfix.sass

// `Clearfix
//--------------------------------------------------

// Can be added to other style rules via:
//
// #foobar
//   @extend .clearfix

.clearfix
  zoom: 1
  &:before, &:after
    content: '.'
    display: block
    overflow: hidden
    visibility: hidden
    font-size: 0
    line-height: 0
    width: 0
    height: 0
  &:after
    clear: both

example.sass

.clearfix
  zoom: 1
  &:before, &:after
    content: '.'
    display: block
    overflow: hidden
    visibility: hidden
    font-size: 0
    line-height: 0
    width: 0
    height: 0
  &:after
    clear: both

.test
  @extend .clearfix

// Compiles to

.clearfix, .test {
  zoom: 1;
}
.clearfix:before, .test:before, .clearfix:after, .test:after {
  content: ".";
  display: block;
  overflow: hidden;
  visibility: hidden;
  font-size: 0;
  line-height: 0;
  width: 0;
  height: 0;
}
.clearfix:after, .test:after {
  clear: both;
}