SASS 3.3

gistfile1.sass

$social: (twitter, $Twitter),
        (facebook, $FB),
        (googleplus, $GPlus),
        (linkedin, $LinkedIn);


@each $socialnetwork, $color in $social {
  .social-link--#{$socialnetwork} {
    background-color: $color;
    &:focus,
    &:hover {
      background-color: darken($color,5%);
    }    
    &:before {
      background-image: url('/images/#{$socialnetwork}.png');
    }
  }
}