Flat has both light and dark themes. You can change your theme by clicking your avatar in the upper right corner and choosing Settings, then visiting the Personal Settings | Appearance section.
Step-by-step
Choosing your theme
Flat has two appearance themes:
- Light mode
- Dark mode
To change your theme, visit Personal Settings | Appearance.
Following your operating system
You can tell Flat to follow your operating system's light/dark preference. Visit Personal Settings | Appearance and select Follow system from the dropdown.