For the mobile translator, the dark mode was probably not ready yet, but an update has readjusted the design.
Google has updated the translator’s mobile app again in recent days and optimized the dark layout. The previous implementation was not visually successful, for example the action bar was still wrapped in blue and with it the Android status bar. Even the area of the language that it was translated into was shrouded in a very light and deep blue all the way.
Google Translate shines in the dark design now finished
Google seems to have seen that the dark design was not yet optimal. One of the latest updates has now improved, the translator app is completely dark and therefore looks much better. See my screenshots:
In the settings of each Google application, you can specify whether the dark mode should be activated or not. Also, if the application should be based on the system configuration. It only works from Android 9.