Is it obligatory to make up for the fast of the day on which menstruation ceased before Fajr, and no discharge was seen, but ghusl was not performed until minutes before Maghrib, and light pinkish or brownish discharge, tending towards yellowish, appeared before the Fajr of the following day, followed by the "white discharge" (al-qassah al-bayda') after the Fajr adhan, with doubt about seeing a small spot of the same color as the discharge after the Fajr adhan?

A woman recognizes purity by one of two signs: the white discharge (al-qassah al-bayda') or complete dryness (al-jufūf). The questioner mentioned seeing complete dryness and intending to fast after Fajr, then seeing a yellowish or brownish discharge on the second day. This action is correct, as is the fasting. The yellowish or brownish discharge after purity is not to be considered, based on the hadith (definition) of Umm Atiyyah: "We did not consider the yellowish or brownish discharge after purity to be anything."