Only a few Google apps and services on the web have enabled the dark mode feature. The latest addition to this list is Google Drive. News 9 to 5 Google.
The feature is continuously being rolled out globally. Users now can turn dark mode on or off by clicking the gear icon in the top-right corner and then going to Settings > General & Appearance.
The new feature does not automatically support the device’s dark mode. So those who want to use dark mode should enable it from settings. However, the first time the feature is enabled, Google will show a popup about it.
Google Keep, and Chat support dark theme. Even if Gmail has dark mode, it does not change the content view of the email.