Using NPOI, create Excel file from an existing file, retaining formatting

CreateXLS.cs

    private void CreateExcel(SalarySummary o, List<SalaryInfo> l, string path)
    {
      try
      {
        var temp = $"{path}salary-template.xlsx";
        var nFile = $"{path}{o.period}.xlsx";

        System.IO.File.Copy(temp, nFile, true);

        //using (var fs = new FileStream(nFile, FileMode.OpenOrCreate, FileAccess.ReadWrite))
        using (var fs = System.IO.File.OpenRead(nFile))
        {
          var wb = new XSSFWorkbook(fs);
          var ws = wb.GetSheetAt(0);
          var ix = 6;

          ws.GetRow(1).GetCell(8).SetCellValue(o.period);

          var f_sn = ws.GetRow(ix + 1).GetCell(1).CellStyle;
          var f_name = ws.GetRow(ix + 1).GetCell(2).CellStyle;
          var f_acc = ws.GetRow(ix + 1).GetCell(3).CellStyle;
          var f_amt1 = ws.GetRow(ix + 1).GetCell(4).CellStyle;
          var f_amt2 = ws.GetRow(ix + 1).GetCell(8).CellStyle;

          foreach (var x in l)
          {
            ix++;
            var r = ws.CreateRow(ix);

            var c1 = r.CreateCell(1); c1.SetCellValue(ix - 7); c1.CellStyle = f_sn; // S/N
            var c2 = r.CreateCell(2); c2.SetCellValue(x.name); c2.CellStyle = f_name; // Guard's Name
            var c3 = r.CreateCell(3); c3.SetCellValue(x.bank); c3.CellStyle = f_name; // Bank
            var c4 = r.CreateCell(4); c4.SetCellValue(x.account); c4.CellStyle = f_acc; // Account

            var c5 = r.CreateCell(5); c5.SetCellValue((double)x.salary); c5.CellStyle = f_amt1; // Salary
            var c6 = r.CreateCell(5); c6.SetCellValue((double)x.overtime); c6.CellStyle = f_amt1; // Overtime
            var c7 = r.CreateCell(5); c7.SetCellValue((double)x.bonus); c7.CellStyle = f_amt1; // Bonus
            var c8 = r.CreateCell(5); c8.SetCellValue((double)x.offences); c8.CellStyle = f_amt2; // Penalty
            var c9 = r.CreateCell(5); c9.SetCellValue((double)x.absent); c9.CellStyle = f_amt2; // Absent Fee
            var c0 = r.CreateCell(5); c0.SetCellValue((double)x.net); c0.CellStyle = f_amt1; // Payable Salary
          }

          wb.Write(fs);
        }
      }
      catch
      {
      }
    }