Vue --- Ant --- Component drop-down menu style

 <h3 style="margin-bottom: 15px">单人课程统计</h3>
            <a-dropdown :trigger="['click']">
              <a class="ant-dropdown-link" style="font-size: 16px;">
                全部(队员:{{ people }}) <a-icon type="down" />
              </a>
              <a-menu slot="overlay">
                <a-col :md="24" :lg="3">
                  <a-menu-item v-for="item in peopleTreeData" :key="item.course_id" style="width: 160px">
                    <a href="" style="font-size: 16px" @click.prevent="linkClick(item)">{{ item.course_name }}-{{ item.course_times }}</a>
                  </a-menu-item>
                </a-col>
              </a-menu>
            </a-dropdown>

<style lang="less" scoped>
  li{
    margin-left: 10px;
    width: 138px;
    list-style: none;
    line-height: 2rem;
    color: black;
    transition: background-color 1s linear,color 1s linear;
    -webkit-transition: background-color 1s linear,color 1s linear;
    -moz-transition: background-color 1s linear,color 1s linear;
    -o-transition: background-color 1s linear,color 1s linear;
  }
  li:hover{
    background-color: #ADFF2F;
    color: blue;
  }
  .ant-dropdown-menu{
    padding: 0px 0;
  }