Sass + Compass Twitter bootstrap custom button color mixin

bootstrap_btn_color_mixin.sass

=btn_color($primary)
  $secondary: adjust-saturation(adjust-lightness($primary, 9), 37)
  $tertiary: adjust-saturation(adjust-lightness($primary, 22), 5)

  color: #ffffff
  text-shadow: 0 -1px 0 rgba(0, 0, 0, 0.25)
  background-color: $primary
  *background-color: $tertiary
  +background-image(linear-gradient(top, $secondary, $primary))
  background-repeat: repeat-x
  border-color: $primary $primary $secondary
  border-color: rgba(0, 0, 0, 0.1) rgba(0, 0, 0, 0.1) rgba(0, 0, 0, 0.25)
  &:hover, &:focus, &:active, &.active, &.disabled, &[disabled]
    color: #ffffff
    background-color: $primary
    *background-color: #003bb3
  &:active, &.active
    background-color: #003399 \9