Amazon announced three new Kindles today, which bring updated colors, thinner and lighter profiles and longer-lasting batteries. All versions now come with flush displays and optional aluminum backs.The basic Kindle (12th generation) features the same-sized 6-inch e-ink screen but with more rounded corners and a seamless flush display. This allowed Amazon to expand the color options, with the borders around the display getting the same hues as the rest of the device.Amazon Kindle 12th genUbe is the new hero color. It’s a deep purple shade, and it’s joined by graphite black...