1.改变最外层边框

  .el-table td,

  .el-table th.is-leaf,

  .el-table–border,

  .el-table–group {

    border-color: black;

  }

  .el-table–border::after,

  .el-table–group::after,

  .el-table::before {

    background-color: black;

  }

2.在el-table添加属性 :cell-style=”cellStyle” 改变表格里面的边框颜色。

:header-cell-style=”{ color: ‘black’, borderColor: ‘black’ }”，改变表头的边框颜色，

3.在methods添加函数：

cellStyle({ row, column, rowIndex, columnIndex }) {

        return ‘border-color:black!important; color:#000000!important’;

      },