Is fasting and prayer valid if menstruation occurs after forty days for four days, then stops for two days, and on the third day dark-colored discharge appears?

The maximum duration of postpartum bleeding (nifas (definition)) is forty days. If the nifas stops, then any blood that appears afterwards is considered menstruation (hayd) if it coincides with the usual menstrual period; otherwise, it is considered irregular bleeding (istihada). As for dark discharges (yellowish or brownish) after purification from menstruation, they are not considered menstruation unless they are connected to blood or occur during the usual menstrual period.