Last week I attend the CodePen Show & Tell at ConvergeSE. While there, I demoed Container Queries using a collection of demos I posted on CodePen. If you’re not familiar with Container Queries (a.k.a. Element Queries) I highly recommend checking out my talk on the subject from CSS Dev Conf last October, or checkout this list of resources.
Container Queries are still in an early concept state. More work needs done to make this a browser standard, but things still seem optimistic. There is need for more and more use cases though, and polyfills are a great start. Consider taking one of the polyfills from the collection for a spin. Hit me up on Twitter if you have a new demo to add to the collection.