What is the ruling concerning my fasting and prayers for the four days that followed my seeing a thin, light brown line, during which I fasted and prayed without performing ghusl, before I saw the white discharge, which was said to be a sign of purity, and then performed ghusl?

If a woman performs ghusl after verifying the cessation of menstruation and the dryness of the area, and then sees a yellowish discharge after her usual days of menstruation have ended, this is not considered menstruation. This is because the discharge of turbid or yellowish fluid after purification is not considered menstruation. However, if the yellowish discharge occurs before the cessation of blood and before purification is verified, then it is considered menstruation. In this case, she must make up the fast of that day if the discharge appeared after Fajr, and prayer is not valid until after a second ghusl.