$color: red;

@mixin color {
  margin: 0 auto;
  color: $color;
}

div {
  div {
    div {
      div {
        div {
          div {
            color: $color;
          }
        }
      }
    }
  }
}

.insert {
  display: block
}

.alter:after {color: red; content: 'example'}

.delete div div div div div div div div {
  display: block;;
}