Evolution of detailed system parameters in the model. Panel (a):Variations in the orbital period and mass ratio with evolutionary time. Other panels: Roche lobe mass transfer rate evolution (b), radii of both components and their corresponding Roche lobe radii (c), central temperature evolution (d), mass changes of both components (e), and convective core mass variations for both components (f). The right panels mirror the left panels but magnify the first episode of rapid mass transfer. The light gray area marks the contact phase in the conservation case. The “r1” denotes the first reverse mass transfer episode (from the initially less massive to the more massive star), while “f1” indicates the first forward mass transfer episode (from the initially more massive to the less massive star).