What are the differences between the Audi 80 and Audi A4?

I am looking to purchase an Audi and considering both the 80 and A4 models, but I'm not sure what sets them apart. Can someone break down the key differences for me?

The Audi A4 is the successor to the Audi 80, with significant improvements in design, technology, and performance. The A4 has a sportier and more modern look, as well as upgraded features and a more powerful engine.

While the Audi 80 is an older model, it is known for its reliability and durability. The A4 is a newer model with more advanced technology, but the 80 may be a more budget-friendly option.