Dark Mode has become very famous in last few years. Most of the apps that we are using now a days have added the dark mode support. It has also been given in most of the Google apps which includes the Search app itself. Just a few days ago we saw Google testing pitch black theme on the search results in the desktop web version. The test has been followed up with new darker shade on Google app on Android phones.
The new color is not as black as the shade we have seen on the web version that one was literally pitch black and this one is just the darker shade of gray though it is quite closer to black. The change is more evident in the Discover feed which has become considerably darker. Search results have also got a new and darker shade but the change is not that significant. The redesign has not been rolled widely but if you want to try this out you can download latest 13.8 beta from Google Play Store.