While neat technically speaking, I unfortunately can't say the result is acceptable for any kind of professional work, in my opinion.

For example, take a close look at the iPhone X in the "Device Library" list, the device and "notch" borders are butchered beyond recognition. A key component of the iPhone X's brand are the particular rounded corners used for the notch, and if the point of this project is to closely emulate particular devices instead of generic ones, it woefully missed the mark.

To be fair, I can't speak for the accuracy for the other devices included, but if their implementations are at all similar to the iPhone X's, I'd expect they are also poor representations.

Comparison between the CSS "iPhone X" and an accurate representation: https://notebook.barrowclift.me/dropbox/comparison.png, and a Light read for more information on the iPhone X corners: https://medium.com/tall-west/no-cutting-corners-on-the-iphon...