@include b(collapse) {
  & + & {
    @include border($top: 0, $left: 0);
  }

  position: relative;
  &.is-active {
    .#{$namespace}-cell {
      .icon-down {
        -webkit-transform: rotate(180deg);
        transform: rotate(180deg);
      }
    }
  }
  .#{$namespace}-cell {
    .icon-down {
      -webkit-transform: rotate(0deg);
      transform: rotate(0deg);
      -webkit-transition-duration: .3s;
      transition-duration: .3s;
      -webkit-transition-timing-function: linear;
      transition-timing-function: linear;
    }
  }
  &-wrapper {
    position: relative;
    overflow: hidden;
    -webkit-will-change: height;
    will-change: height;
    -webkit-transition: height .3s ease-in-out;
    transition: height .3s ease-in-out;
  }
  &-content {
    @include border($top: 0);

    padding: 10px 15px;
    background-color: $white;
  }
}