gistfile1.scss

@mixin button($background_base, $height: 39px, $left-pad: 5, $padding: 15, $background_ext: '.png') {
  display: inline-block; 
  background: image-url('buttons/left_#{$background_base}#{$background_ext}') no-repeat left top;
  padding-left: $left-pad + px;
  span {
    display: block;
    background: image-url('buttons/right_#{$background_base}#{$background_ext}') no-repeat right top;
    height: $height;
    padding-left: $padding - $left-pad + px;
    padding-right: $padding + px;
  }
  &:active { 
    background: image-url('buttons/left_#{$background_base}_down#{$background_ext}') no-repeat left top;
    span {
      background: image-url('buttons/right_#{$background_base}_down#{$background_ext}') no-repeat right top;
    }
  }
}