When you add a container query, it will look for the nearest ancestor container, by default. If you have multiple nested containers or if you just want to make sure that your query uses the right container, you can name containers and query them specifically.
You can use media queries to style elements based on features of the browser viewport, for example, min-width, max-height, or orientation. With container queries, you can now do the same but with any parent element. Instead of the viewport, you can now listen to properties and features of a containing element.