There are times where you need to reset a an element’s styles. Instead of overwriting it with even more style declarations, you can simply reset them.
Yes, i totally agree to @RobertSmith that it is important to know this property can't be used in project, where reliable xbrowser support is needed. It is a very interesting property nonetheless. http://caniuse.com/#search=unset
This course is broken.
from this url (https://egghead.io/lessons/css-easily-reset-styles-with-a-single-css-value)
The next segment is from a React course.
This is a very neat trick that I was unaware of. I think it's worth mentioning to the audience however, that this unfortunately is not supported on IE11 or below according to the Can I use database.