@mixin placeholder($color) {
  &::-webkit-input-placeholder { /* Chrome/Opera/Safari */
    color: $color;
  }

  &::-moz-placeholder { /* Firefox 19+ */
    color: $color;
  }

  &:-ms-input-placeholder { /* IE 10+ */
    color: $color;
  }

  &:-moz-placeholder { /* Firefox 18- */
    color: $color;
  }
}