Yes, Todoist has dark themes for all your devices!
Learn how turn it on by changing your color themes.
Q: Does Todoist offer a true black theme for (AM)OLED screens?
A: No. Even though a true black theme would save some battery over our current dark theme, we don’t regard the difference in power consumption significant enough (0.3% mW). Additionally, without an entire redesign, supporting a true black theme would make it harder to distinguish visual hierarchies and depth.