element-ui中Select 选择器去除点击时的淡蓝色边框

<el-select   v-model="tenantCont" placeholder="请输入机构标识">
     <el-option-group
         v-for="group in options"
         :key="group.label"
         :label="group.label">
            <el-option
                v-for="item in group.options"
                :key="item.value"
                :label="item.label"
                 :value="item.value">
             </el-option>
       </el-option-group>
 </el-select>

// 去除点击时候的淡蓝色边框
.my-el-select /deep/ .el-input .el-input__inner {
   border-color: #DCDFE6  !important;
}