.sign-in-button
  &.facebook
    +button($bg: #2d4486)
    .icon
      @extend .fa, .fa-2x, .fa-facebook
      margin-right: 10px
    .text
      // huh?
  &.instagram
    +button($bg: #ddd)
    .icon
      @extend .fa, .fa-2x, .fa-instagram
      margin-right: 10px
    .text
      // huh?