Last month, Google announced that a new, Material Design laden sign in screen was coming to everyone. The original plan was that it would roll out June 14th but due to “unforeseen delays”, it is now rolling out over a month later.
Functionally, you aren’t going to find anything different in this new sign in screen other than the brighter, more contemporary Material Design look to it. It does exactly what you would expect it to do which is to allow you to sign into your Google account. But the update brings the site in line with many other Google apps and services as the Mountain View company has been working diligently on updating their wares to Material Design.