What is incumbent upon an unmarried girl who experiences light and irregular menstrual bleeding and doubts her purity for prayer? Is ghusl (ritual bath) required upon seeing a small amount of blood?

The determining factor for menstruation is the presence or absence of blood. So, whenever blood is seen and it continues for a day and a night, it is considered menstruation, and prayer and fasting are prohibited during it. When the bleeding stops, one should perform ghusl (definition) (ritual bath) and resume acts of worship. If the bleeding is less than a day and a night, it is not considered menstruation, and it does not prohibit prayer or fasting. The days when there is no bleeding are considered days of purity.