How does the Audi A8 implement its all-wheel steering system?

I've read that the Audi A8 has an advanced all-wheel steering system, but I'm not quite sure how it works. Can someone explain the details of its implementation?

The Audi A8 uses a rear-axle steering system which dynamically adjusts the steering angle of the rear wheels. This allows for improved handling and stability, particularly at high speeds or tight turns.

The all-wheel steering system in the Audi A8 also has multiple driving modes, including Comfort, Auto, and Dynamic, each with its own steering and stability settings.