var namedStyle = new GC.Spread.Sheets.Style();
namedStyle.name = "style1";
namedStyle.backColor = "green";
activeSheet.addNamedStyle(namedStyle);
activeSheet.setStyleName(1, 1, "style1"); // cell(1,1)'s backColor is green.
 
var namedStyle1 = new GC.Spread.Sheets.Style();
namedStyle1.name = "style2";
namedStyle1.parentName = "style1";
namedStyle1.foreColor = "red";    // the namedStyle's foreColor is red.
activeSheet.addNamedStyle(namedStyle1);
activeSheet.setStyleName(2, 1, "style2");