Toggle classes for changing icon or content inside a toggle

toggle.scss

.toggle {
  .open { display: none; }
  .closed { display: block; }

  &--active {
    .open { display: block; }
    .closed { display: none; }
  }
}

.collapse-toggle {
  .open,
  .closed {
    margin: 0 auto;
  }

  .open { display: block; }
  .closed { display: none; }

  &.collapsed {
    .open { display: none; }
    .closed { display: block; }
  }
}