The Amazon Kindle Paperwhite 4 e-reader came out in November 2018 and the only color available to purchase was black. The company just added a new color that is available right now and it is called Twilight Blue, this is apropo, because it is waterproof.
The entire back of the Paperwhite 4 is blue and so are the very edges of the front of the bezel. The Micro USB and power button are also blue. The front of the device is still predominantly black. I think the twilight blue adds a nice blue hue to the front of the device.
https://goodereader.com/blog/kindle/...-twilight-blue