amis/packages/amis-ui/scss/components/_dropdown.scss

.#{$ns}DropDown {
  position: relative;
  display: inline-block;

  &-caret {
    margin-left: var(--DropDown-caret-marginLeft);
    display: inline-block;
    vertical-align: top;
    transition: transform var(--animation-duration) ease;

    > svg {
      width: px2rem(10px);
      height: px2rem(10px);
      top: 0.125em;
    }
  }

  &.is-opened &-caret {
    transform: rotate(180deg);
  }

  &.is-actived {
    .#{$ns}Button {
      color: var(--link-color);
    }
  }

  &--block {
    display: block;

    .#{$ns}Button {
      display: block;
    }
  }

  &-menu {
    background: var(--DropDown-menu-bg);
    list-style: none;
    padding: var(--DropDown-menu-paddingY) var(--DropDown-menu-paddingX);
    margin: 0;
    min-width: var(--DropDown-menu-minWidth);
    text-align: left;
    border: none;
    user-select: none;

    &-root {
      position: absolute;
      z-index: $zindex-dropdown;
      top: 100%;
      left: 0;
      margin: px2rem(1px) 0 0;
      border: none;
      border-radius: var(--DropDown-menu-borderRadius);
      box-shadow: var(--DropDown-menu-boxShadow);
      min-width: var(--DropDown-menu-minWidth);
      overflow-y: auto;
      overflow-x: hidden;
      max-height: px2rem(300px);
    }
  }

  &--alignRight &-menu {
    left: auto;
    right: 0;
  }

  &-menuItem,
  &-menu > li {
    padding: var(--DropDown-menuItem-paddingY) var(--DropDown-menuItem-paddingX);
    white-space: nowrap;
    box-sizing: border-box;
    height: var(--DropDown-menu-height);
    vertical-align: middle;
    user-select: none;
    color: var(--DropDown-menuItem-color);
    text-decoration: var(--link-decoration);

    &.is-active {
      background: var(--DropDown-menuItem-onHover-bg);
      color: var(--DropDown-menuItem-onActive-color);
    }

    &:not(.is-disabled),
    &:not(.disabled) {
      cursor: pointer;
    }

    &.is-disabled {
      cursor: not-allowed;
      // pointer-events: none;
      color: var(--DropDown-menuItem-onDisabled-color);
      filter: grayscale(80%);
    }

    &.#{$ns}DropDown-divider {
      height: px2rem(1px);
      margin: px2rem(9px) 0;
      overflow: hidden;
      background: var(--DropDown-menu-borderColor);
      padding: 0;
    }

    &.#{$ns}DropDown-groupTitle {
      height: inherit;
      font-size: var(--fontSizeSm);
      padding: var(--gap-xs) var(--gap-xs);
      padding-left: var(--gap-sm);
      color: var(--DropDown-group-color);
      flex-grow: 1;
      cursor: default;

      &:hover {
        background: none;
      }

      span {
        white-space: nowrap;
      }

      & ~ .#{$ns}DropDown-button {
        padding-left: var(--gap-lg);
      }
    }
  }

  &-menuItem,
  &-menu:not(.is-mobile) > li {
    &:hover {
      background: var(--DropDown-menuItem-onHover-bg);
      color: var(--DropDown-menuItem-onHover-color);
    }
  }

  &-menu > li a {
    color: inherit;
    display: block;
    text-decoration: none;
  }

  &-popover {
    border: none;
    box-shadow: none;
    // 如果是在PopOver position: absolute会使overlayNode没有高度 定位不正确
    // 改成static z-index不生效 无法点击操作
    > .#{$ns}DropDown-menu-root {
      position: relative;
    }
  }

  > .#{$ns}Button {
    min-width: unset;
  }
}