Hey everyone!
We’re happy to share that now it’s possible to set a custom background (color, gradient or image) right in the settings:
Currently, this feature is available only in the widgets created after this release. However, the good news is that we can manually update your existing widgets on our end 
Check this post for more details - Countdown Timer: [MAJOR UPDATE] Auto-repeat option, layout enhancements, new buttons, themes and more! 