Vue框架的element组件table文字居中

   <el-table max-height="500px" :data="datas.roles" 
    style="width: 100%" border :header-cell-style="{textAlign: 'center'}" :cell-style="{ 
       textAlign: 'center' }">
      <el-table-column prop="id" label="序号" width="100px" />
      <el-table-column prop="name" label="角色名称" width="100px" />
      <el-table-column label="操作" width="180px">
      </el-table-column>
    </el-table>