Claiming a culture of sexual harassment and gender bias at Nike that left women demeaned and underpaid, two former employees sued the sports apparel company late Thursday, demanding more equitable policies.  The federal lawsuit, which seeks class action status, was filed on behalf of Kelly Cahill and Sara Johnston...Both women left Nike...because of the hostile work environment, according to the complaint.  They said in the lawsuit that Nike spent years hiring women at lower salaries than men, discriminating against women during performance reviews and promoting female employees less frequently than male counterparts doing comparable work...The women also said that complaints to human resources about sexual harassment were ignored or mishandled.  In a statement..., Nike said that it “opposes discrimination of any type.”...[T]he lawyers for Ms. Cahill and Ms. Johnston said that the lawsuit, which requires a judge’s certification to be considered a collective action, could cover more than 500 women. No hearing date has been set.  The lawsuit asks that Nike craft standards to ensure equal pay, fair promotion procedures and nondiscriminatory performance evaluations...