ant-design-vue/components/vc-cascader/assets/index.less

.effect() {
  animation-duration: .3s;
  animation-fill-mode: both;
  transform-origin: 0 0;
}

.rc-cascader {
  font-size: 12px;
  &-menus {
    font-size: 12px;
    overflow: hidden;
    background: #fff;
    position: absolute;
    border: 1px solid #d9d9d9;
    border-radius: 6px;
    box-shadow: 0 0 4px rgba(0,0,0,0.17);
    white-space: nowrap;

    &-hidden {
      display: none;
    }

    &.slide-up-enter, &.slide-up-appear {
      .effect();
      opacity: 0;
      animation-timing-function: cubic-bezier(0.08, 0.82, 0.17, 1);
      animation-play-state: paused;
    }

    &.slide-up-leave {
      .effect();
      opacity: 1;
      animation-timing-function: cubic-bezier(0.6, 0.04, 0.98, 0.34);
      animation-play-state: paused;
    }

    &.slide-up-enter.slide-up-enter-active&-placement-bottomLeft,
    &.slide-up-appear.slide-up-appear-active&-placement-bottomLeft {
      animation-name: SlideUpIn;
      animation-play-state: running;
    }

    &.slide-up-enter.slide-up-enter-active&-placement-topLeft,
    &.slide-up-appear.slide-up-appear-active&-placement-topLeft {
      animation-name: SlideDownIn;
      animation-play-state: running;
    }

    &.slide-up-leave.slide-up-leave-active&-placement-bottomLeft {
      animation-name: SlideUpOut;
      animation-play-state: running;
    }

    &.slide-up-leave.slide-up-leave-active&-placement-topLeft {
      animation-name: SlideDownOut;
      animation-play-state: running;
    }
  }
  &-menu {
    display: inline-block;
    width: 100px;
    height: 192px;
    list-style: none;
    margin: 0;
    padding: 0;
    border-right: 1px solid #e9e9e9;
    overflow: auto;
    &:last-child {
      border-right: 0;
    }
  }
  &-menu-item {
    height: 32px;
    line-height: 32px;
    padding: 0 16px;
    cursor: pointer;
    white-space: nowrap;
    overflow: hidden;
    text-overflow: ellipsis;
    transition: all 0.3s ease;
    position: relative;
    &:hover {
      background: tint(#2db7f5, 90%);
    }
    &-disabled {
      cursor: not-allowed;
      color: #ccc;
      &:hover {
        background: transparent;
      }
    }
    &-loading:after {
      position: absolute;
      right: 12px;
      content: 'loading';
      color: #aaa;
      font-style: italic;
    }
    &-active {
      background: tint(#2db7f5, 80%);
      &:hover {
        background: tint(#2db7f5, 80%);
      }
    }
    &-expand {
      position: relative;
      &:after {
        content: '>';
        font-size: 12px;
        color: #999;
        position: absolute;
        right: 16px;
        line-height: 32px;
      }
    }
  }
}

@keyframes SlideUpIn {
  0% {
    opacity: 0;
    transform-origin: 0% 0%;
    transform: scaleY(.8);
  }
  100% {
    opacity: 1;
    transform-origin: 0% 0%;
    transform: scaleY(1);
  }
}
@keyframes SlideUpOut {
  0% {
    opacity: 1;
    transform-origin: 0% 0%;
    transform: scaleY(1);
  }
  100% {
    opacity: 0;
    transform-origin: 0% 0%;
    transform: scaleY(0.8);
  }
}

@keyframes SlideDownIn {
  0% {
    opacity: 0;
    transform-origin: 0% 100%;
    transform: scaleY(0.8);
  }
  100% {
    opacity: 1;
    transform-origin: 0% 100%;
    transform: scaleY(1);
  }
}
@keyframes SlideDownOut {
  0% {
    opacity: 1;
    transform-origin: 0% 100%;
    transform: scaleY(1);
  }
  100% {
    opacity: 0;
    transform-origin: 0% 100%;
    transform: scaleY(0.8);
  }
}