.c-key-value-list {
  @extend %description-list;

  &::after {
    @extend %clearfix;
  }

  .c-key-value-list--border-top {
    border-top: 1px solid $secondary-gray20 !important;
  }

  .c-key-value-list--multiple-values {
    padding-top: 4.375px; //(2 * $base-font-size - $base-line-height) / 2
    padding-bottom: 4.375px;
    border: none;
    line-height: $base-line-height;
  }

  .c-key-value-list__key {
    @extend %description-list-key;
  }

  .c-key-value-list__value {
    @extend %description-list-value;
  }

  .c-key-value-list__key--full-width {
    width: 100%;
  }

  .c-key-value-list__value--full-width {
    width: 100%;
    padding: 0 20px;
    float: none;
  }

  .c-key-value-list__content {
    display: inline-block;
    max-height: 100px;
    margin: 0;
    padding-left: 16px;
    transition: max-height .5s linear;
    border-top: none;
    line-height: 20px;
    text-overflow: ellipsis;
    white-space: pre-line;
    overflow: hidden;
    box-sizing: content-box;
  }
}

.c-key-value-list {
  @extend %description-list;

  &::after {
    @extend %clearfix;
  }

  .c-key-value-list--border-top {
    border-top: 1px solid $secondary-gray20 !important;
  }

  .c-key-value-list--multiple-values {
    padding-top: 4.375px; //(2 * $base-font-size - $base-line-height) / 2
    padding-bottom: 4.375px;
    border: none;
    line-height: $base-line-height;
  }

  .c-key-value-list__key {
    @extend %description-list-key;
  }

  .c-key-value-list__value {
    @extend %description-list-value;
  }

  .c-key-value-list__key--full-width {
    width: 100%;
  }

  .c-key-value-list__value--full-width {
    width: 100%;
    padding: 0 20px;
    float: none;
    border-top: none;
  }

  .c-key-value-list__content {
    display: inline-block;
    max-height: 100px;
    margin: 0;
    padding-left: 16px;
    transition: max-height .5s linear;
    border-top: none;
    line-height: 20px;
    text-overflow: ellipsis;
    white-space: pre-line;
    overflow: hidden;
    box-sizing: content-box;
  }
}

Fix thick line if full-width description is empty
Fix thick line if full-width description is empty
