element-ui: el-table设置表头和单元格的颜色

<el-table :data="dataArray" :cell-style="cellStyle" :header-cell-style="{ 
      background:'#0000CD',height:'30px',color:'#000000CD',border: '1px solid tan'}">
    <el-table-column prop="name" label="国家" width="180" />
    <el-table-column prop="value" label="地区" />
  </el-table>

methods: {

      cellStyle({ row, column, rowIndex, columnIndex }) {
        return "backgroundColor:#000080";


    }
    },