a130/_sass/bourbon/css3/_border-radius.scss

//************************************************************************//
// Shorthand Border-radius mixins
//************************************************************************//
@mixin border-top-radius($radii) {
  @include prefixer(border-top-left-radius, $radii, spec);
  @include prefixer(border-top-right-radius, $radii, spec);
}

@mixin border-bottom-radius($radii) {
  @include prefixer(border-bottom-left-radius, $radii, spec);
  @include prefixer(border-bottom-right-radius, $radii, spec);
}

@mixin border-left-radius($radii) {
  @include prefixer(border-top-left-radius, $radii, spec);
  @include prefixer(border-bottom-left-radius, $radii, spec);
}

@mixin border-right-radius($radii) {
  @include prefixer(border-top-right-radius, $radii, spec);
  @include prefixer(border-bottom-right-radius, $radii, spec);
}