The option to activate dark mode at once for multiple applications is one of the new features of Android 10, officially released in early September. With the system update, the new look appeared again in the Google and Assistant app.
The search engine has been testing dark mode in your app since June. It had been released in the beta version for Android, which gained a dark gray background on all screens of the application, including the Google Assistant.
According to users, the dark mode of the Google application was released without updating, indicating a change made to the server. The new look is not yet available to all users, but should be made available gradually.
The dark mode of the apps is aimed at devices running Android 10, but some Android 9 Pie users claim to have received the option as well. To check if it arrived for you, open the Google app, access the Settings area and then the General menu.
If the option can be enabled, the app will show the Theme item. It allows you to keep the old interface, force the use of the new one or follow the standard defined for the system.
Dark mode has already been rolled out to a number of apps, including Calendar, Keep, Photos, Gmail and Play Store. Even in the stable version of Windows 10, Chrome allows you to adopt the new look.
With information: XDA Developers.