notifications-admin/app/assets/stylesheets/components/textbox.scss

.textbox-highlight {

  &-wrapper {
    position: relative;
  }

  &-textbox {
    resize: none;
    z-index: 20;
    background: none;
  }

  &-textbox,
  &-background,
  &-foreground,
  &-mask {
    @include core-19;
    display: block;
    box-sizing: border-box;
    position: relative;
    width: 500px;
    height: 200px;
    margin: 0;
    padding: 4px;
    overflow: hidden;
  }

  &-background,
  &-foreground,
  &-mask {
    position: absolute;
    top: 0;
    left: 0;
    pointer-events: none;
    color: transparent;
    white-space: pre-wrap;
    border: 2px solid transparent;
  }

  &-background {

    z-index: 10;

    .tag {
      background: $light-blue;
      border-radius: 3px;
      color: transparent;
      display: inline;
    }

  }

  &-mask {

    z-index: 30;

    .tag {
      color: $white;
      text-shadow: 0 1px 0 $light-blue, 0 -1px 0 $light-blue;
      position: relative;
      display: inline;
      overflow: hidden;
    }

  }

  &-foreground {

    z-index: 40;

    .tag {
      color: transparent;
      border-radius: 3px;
      overflow: hidden;
      display: inline;
      box-shadow: inset 0.75em 0 0 0 rgba($light-blue, .7),
                  inset -0.75em 0 0 0 rgba($light-blue, .7);
    }

  }


}