Why does the Audi A2 have a lower drag coefficient than other cars?

I've noticed that the Audi A2 has a significantly lower coefficient of drag compared to other cars. Can you explain why?

The Audi A2 has a unique design that focuses on reducing air resistance by incorporating aerodynamic features such as the curved roofline and smoothed body contours. These design elements result in a lower drag coefficient, allowing for better fuel efficiency and improved performance.

Audi engineers put a lot of emphasis on improving the aerodynamics of the A2. By extensively testing and optimizing the car's shape and features in wind tunnels, they were able to achieve a record-breaking drag coefficient of 0.25.