How does Audi A7's quattro system distribute torque between front and rear wheels?

I've heard that Audi's quattro system is known for its handling and grip, but how exactly does it distribute torque between the front and rear wheels?

The Audi A7's quattro system uses a self-locking center differential to distribute torque between the front and rear axles, sending up to 70% of torque to the rear wheels and up to 85% to the front wheels for optimal traction and handling.