Why is the front brake disc larger than the rear brake disc?

Why is the front brake disc larger than the rear brake disc?
When the car moves, the center of gravity of the body begins to shift. In the car, there is a distinct feeling of pushing back. When slowing down, the body will rush forward, and when turning, the body will swing in the opposite direction. In fact, it can be quite simple to understand that at the start of the car, the gravity shifts backward due to the sudden movement of the car forward, from the original 60:40 to 50:50, or higher (depending on the acceleration of the car starting). When the car brakes, also due to the inertia of the car, gravity shifts forward, from 60:40 to 70:30 or higher (regardless of brake speed).
When the car is braking, the resistance provided by the friction between the wheels and the ground, then the car shows the so-called "nod" phenomenon, which also indicates that the positive pressure of the front wheel on the ground is definitely greater than that of the rear wheel, which means that the front disk is larger than the rear disk, the greater the brake force obtained by the brake disc is. When the car brakes, the front wheels gain more braking force because there is more positive pressure on the ground from the front wheels. Therefore, the brake disc of the front wheel is designed to be larger in order to take advantage of this feature. And most of the time the vehicle is moving forward, so most of the time when braking gravity transfer is from the rear to the front, which determines the front wheel brake system of the vehicle must be stronger than the rear wheel, so that the vehicle in need of braking when the vehicle can effectively stop the vehicle.