partnership (مشاركة) is governed by basic Shari‘ah principles, not by one rigid historical procedure. A modern method is not rejected merely because that exact form did not exist earlier.
The form may adapt to changing business needs, provided it does not violate the Qur’an, Sunnah or an established juristic principle.
This distinction will be used repeatedly in later applications. Before calculating profit or designing an exit, first identify who owns what, who works in the business and which rule governs genuine loss.