Why does the Audi A7 have a curved roofline?

I've noticed that the Audi A7 has a distinctive curved roofline, is there a specific technical reason for this design choice?

The curved roofline on the Audi A7 is not just for aesthetics, it actually serves a purpose. It helps improve the car's aerodynamics, reducing drag and improving fuel efficiency.

The curved roofline also adds to the sporty and sleek appearance of the Audi A7. It sets it apart from other sedans and gives it a unique look.