实现效果如下：

代码如下：

                <el-dropdown trigger="click" @command="handleCommand" active-text-color="#606266">
                  <span class="product-card">{{
                    getCategoryName(categoryId)
                  }}</span>
                  <el-dropdown-menu slot="dropdown">
                    <template v-for="(item, index) in categories">
                      <el-dropdown-item
                        class="xlcdList"
                        :style="
                          item.id == categoryId
                            ? 'color: #606266; background-color: #ecf5ff;'
                            : ''
                        "
                        :key="index"
                        :command="item.id"
                        >{{ item.categoryName }}</el-dropdown-item
                      >
                    </template>
                  </el-dropdown-menu>
                </el-dropdown>

.el-dropdown-menu {
  background-color: #478068;
}


.xlcdList {
  background-color: #478068;
  color: white;
  &:hover {
    // background-color: #478068;
    color: #606266;

  }
}