var workbook = new XLWorkbook();
var ws = workbook.Worksheets.Add("Row Cells");
var rowFromWorksheet = ws.Row(1);
rowFromWorksheet.Cell(1).Style.Fill.BackgroundColor = XLColor.Red;
rowFromWorksheet.Cells("2").Style.Fill.BackgroundColor = XLColor.Blue;
rowFromWorksheet.Cells("3,5:6").Style.Fill.BackgroundColor = XLColor.Red;
rowFromWorksheet.Cells(8, 9).Style.Fill.BackgroundColor = XLColor.Blue;
var rowFromRange = ws.Range("A2:I2").FirstRow();
rowFromRange.Cell(1).Style.Fill.BackgroundColor = XLColor.Red;
rowFromRange.Cells("2").Style.Fill.BackgroundColor = XLColor.Blue;
rowFromRange.Cells("3,5:6").Style.Fill.BackgroundColor = XLColor.Red;
rowFromRange.Cells(8, 9).Style.Fill.BackgroundColor = XLColor.Blue;
ws.Columns().Width = 7;
workbook.SaveAs("RowCells.xlsx");