What is the ruling on a woman fasting when a brown discharge appears after the first three days of menstruation?

If the brown discharge connects with blood, it is menses, and fasting is not valid, and it is obligatory to make up for the missed fast.

If it is seen after purification, then it is not menses, and ghusl, prayer, and fasting are obligatory.

If the discharge is continuous, then ablution is required for every prayer after its time has begun.