What is the sign of purity from menstruation, and are yellow or brown discharges after the cessation of blood considered menstruation, and what is the legal period of dryness that necessitates Ghusl?

A woman recognizes the cessation of menstruation by one of two signs: dryness (jufūf) or the white discharge (al-quṣṣah al-bayḍā’). When she observes dryness, ghusl (ritual bath) becomes obligatory for her. If she sees purity by the cessation of blood and any accompanying yellowish or brownish discharge, she should hasten to perform ghusl. Then, if she later sees a yellowish or brownish discharge: if it is within the period of her regular custom (ʻādah), it is considered menstruation; if it is outside the period of her regular custom, it is not considered menstruation according to the Hanbalis, and she must perform ablution (wuḍū’) for each prayer after the prayer time has begun.