Font-Awesome/scss/_mixins.scss

// Mixins

@mixin border-radius($radius) {
  -webkit-border-radius: $radius;
  -moz-border-radius: $radius;
  border-radius: $radius;
}

@mixin icon-stack($width: 2em, $height: 2em, $top-font-size: 1em, $base-font-size: 2em) {
  .icon-stack {
    position: relative;
    display: inline-block;
    width: $width;
    height: $height;
    line-height: $width;
    vertical-align: -35%;
    [class^="icon-"],
    [class*=" icon-"] {
      display: block;
      text-align: center;
      position: absolute;
      width: 100%;
      height: 100%;
      font-size: $top-font-size;
      line-height: inherit;
      *line-height: $height;
    }
    .icon-stack-base {
      font-size: $base-font-size;
      *line-height: $height / $base-font-size;
    }
  }
}

@mixin animation($animation) {
  -moz-animation: $animation;
  -o-animation: $animation;
  -webkit-animation: $animation;
  animation: $animation;
}

@mixin transform($transform) {
  -webkit-transform: $transform;
  -moz-transform: $transform;
  -ms-transform: $transform;
  -o-transform: $transform;
  transform: $transform;
}