message: refactor: select-tree use css var
diff: +@import '../../core-css/index.scss';
  +
  .hi-selecttree {
  &__input {
  width: 320px;
  height: 32px;
  line-height: 32px;
  - border: 1px solid #d8d8d8;
  + border: 1px solid use-color('gray-30');
  box-sizing: border-box;
  border-radius: 2px;
  text-align: left;
  padding: 0 0 0 12px;
  - color: #000;
  + color: use-color('black');
  display: inline-flex;
  justify-content: space-between;
  &:hover {
  - border: 1px solid #4284f5;
  + border: 1px solid use-color('primary');
  .hi-selecttree__input--expand.clearable {
  display: none;
  }
  .hi-selecttree__icon-close:hover {
  - color: #333;
  + color: use-color('black');
  }
  }
  }
  &--placeholder {
  - color: #ccc;
  + color: use-color('gray-50');
  }
  &-icon {
  }
  &__icon-close {
  - color: #bbb;
  + color: use-color('gray-50');
  display: none;
  }
  &__selecteditem {
  flex: 0 0 auto;
  position: relative;
  - // max-width: 60%;
  - // width: 100%;
  height: 22px;
  line-height: 22px;
  padding: 0 20px 0 10px;
  margin: 0 2px;
  overflow: hidden;
  vertical-align: middle;
  - background-color: #f2f2f2;
  + background-color: use-color('gray-10');
  border-radius: 2px;
  text-align: left;
  box-sizing: border-box;
  }
  &__popper {
  - background: #fff;
  + background: use-color('white');
  box-shadow: 0 2px 8px 0 rgba(0, 0, 0, 0.15);
  border-radius: 2px;
  max-height: 300px;
  }
  &__searchbar-wrapper {
  - background-color: #fff;
  + background-color: use-color('white');
  width: 100%;
  padding: 0 12px;
  box-sizing: border-box;
  &__searchbar-inner {
  height: 36px;
  - border-bottom: 1px solid #e6e7e8;
  + border-bottom: 1px solid use-color('gray-30');
  box-sizing: border-box;
  display: flex;
  align-items: center;
  padding: 0 2px;
  .hi-selecttree_searchbar__icon-close {
  - color: #ccc;
  + color: use-color('gray-50');
  cursor: pointer;
  }
  .hi-selecttree_searchbar__icon-close:hover {
  - color: #333;
  + color: use-color('black');
  }
  }
  