Is the fast considered valid if light red-yellowish blood is discharged after six days of menstruation, and this blood is considered istihadah (non-menstrual bleeding) due to its characteristics being different from menstrual blood, knowing that complete purity has not occurred after the total cessation of blood?

Any blood seen by a woman during her menstrual period, provided that the duration of its days and the intervening purity does not exceed fifteen days, is considered menstruation. If the bleeding exceeds this duration, it becomes clear that the woman is experiencing istihadah (non-menstrual vaginal bleeding). In this case, she should refer to her previous custom (habitual period), or if not, to the valid distinguishing characteristics of the blood. Referring to these signs is only done after the blood and any intervening purity exceed fifteen days. The woman must abstain from prayer, fasting, and whatever a menstruating woman abstains from until the blood ceases, along with any attached yellowish or brownish discharge, as long as it does not exceed the maximum duration of menstruation. She must make up the fasts for the days on which she saw this blood. As for the period of purity between two instances of bleeding, it is a valid state of purity in which prayer and fasting are permissible.