Progressive enhancement is basically how well will content be presented in a variety of browsers. The main idea is to understand how your content is presented on the web because it is the most important aspect, people go to see your content, not your design.
You have to think about the layers of content. Your HTML, CSS, and JavaScrpit and how those work in a different browser. Not everyone has a different browser isn’t at the same level. Understanding progressive enhancement is easy because you want to create content that is usable for any user that comes to your site.
I did not understand what progressive enhancement was so I followed the link to Wikipedia that gave an outline of what progressive enhancement, so I could understand progressive enhancement better. After reading the page, I was able to better understand what progressive enhancement was to better understand the page that was assigned to read.
It is important to understand this because so many people have different browsers and different versions of the browsers.
https://en.wikipedia.org/wiki/Progressive_enhancement