Format cell contents in OpenXML

Hello,
I have create excel sheet with OpenXML libraries. I want to format some row, Like making it bold and changing the background color. I din't get any help from google.
Can anyone help me here plz.
 Here is my sample code.
var ms = new MemoryStream(); spreadsheetDocument = SpreadsheetDocument.Create(ms, SpreadsheetDocumentType.Workbook);WorkbookPart workbookpart = spreadsheetDocument.AddWorkbookPart();workbookpart.Workbook = new Workbook(); uint sheetId = 1;spreadsheetDocument.WorkbookPart.Workbook.Sheets = new Sheets(); Sheets sheets = spreadsheetDocument.WorkbookPart.Workbook.GetFirstChild<Sheets>(); WorksheetPart wsPart = workbookpart.AddNewPart<WorksheetPart>(); Sheet sheet = new Sheet() { Id = spreadsheetDocument.WorkbookPart.GetIdOfPart(wsPart), S ...