non IE11 Plus Minus Animation

_plus-minus-animation.scss

// Plus Minus Animation
// will not function in IE11 http://caniuse.com/#search=flex
// ========================================================================= */
@mixin plus-minus {
  @include flexbox();
  @include align-items(center);
  @include justify-content(center);

  &:before,
  &:after {
    @include transition(transform 500ms ease);
    content: '';
    width: 20px;
    height: 2px;
    position: absolute;
    background-color: $darkness;
  }

  &:before {
    @include transform(rotate(90deg));
  }

  &:after {
    @include transform(rotate(0deg));
  }
}

@mixin plus-minus-animation {

  &:before {
    @include transform(rotate(180deg));
  }

  &:after {
    @include transform(rotate(180deg));
  }
}