What is the most common issue with the Audi A2's braking system?

I've noticed that my Audi A2's brakes are starting to feel less responsive. Is this a common issue with this model and how can I fix it?

The most common issue with the Audi A2's braking system is air in the brake lines. This can cause a spongy feeling when pressing down on the brake pedal and reduced braking performance. To fix this, you will need to bleed the brakes to remove the air from the lines.