How does the aerodynamic design of the Audi A2 improve fuel efficiency?

I've heard that the Audi A2 has a unique aerodynamic design, but I'd like to know how exactly it helps with fuel efficiency. Can someone explain this in more detail?

The Audi A2's streamlined body design reduces air resistance, allowing for a smoother drive and better fuel efficiency.

The sharp edges and flaps on the A2's front bumper help to direct air flow away from the wheels, minimizing turbulence and improving fuel economy.

In addition to its aerodynamic design, the A2 also uses lightweight materials and a highly efficient engine to further enhance fuel efficiency.