.icon {

  &::before {
    font-size: 18px;
  }
  &-xsmall::before {
    font-size: 12px;
  }
  &-small::before {
    font-size: 15px;
  }
  &-large::before {
    font-size: 20px;
  }
  &-xlarge::before {
    font-size: 30px;
  }
}

.children-icon {

  *::before {
    font-size: 18px;
  }

  &-xsmall>*::before {
    font-size: 12px;
  }

  &-small>*::before {
    font-size: 15px;
  }

  &-large>*::before {
    font-size: 20px;
  }

  &-xlarge>*::before {
    font-size: 30px;
  }
}