Appearance
Make Tweek look the way you like: light or dark, a preset theme, or one of your own. Your choice follows your account, so it shows on all your devices.
Light or dark
Go to Settings → Appearance → Color mode and choose Light, Dark or System. System switches along with your device.

On some phones, Xiaomi for example, the system’s own dark theme can recolor apps on top of Tweek’s dark mode and change its shade. If the colors look off, turn off forced dark mode for Tweek in your phone’s display settings.
Color themes
Go to Settings → Appearance and pick one of seven themes under Preset themes. Three of them (Tweek, Jay and Tody) are free; the others need Premium.

Your own theme
On Premium you can build your own. A custom theme has two colors — accent and background — set separately for light and dark mode, so it looks right in either.
On the web, go to Settings → Appearance and click Create new under Custom themes. Pick the light mode colors, then the dark mode colors, then name the theme and click Create theme.

To change or remove a theme later, open its menu in the Custom themes list and choose Edit or Remove. Removing a theme deletes it from all your devices.
In the iOS app, you’ll find the same Create new button under Settings → Appearance. The Android app can’t create themes yet, but it shows the ones you made on the web or iPhone, and you can pick them there.
Font
The font can’t be changed for now.