hubleto-community You may change the Hubleto's UI theme in Settings -> Change theme. There are lots of prebuilt themes available. If you are running Hubleto locally, you can change the design of the desktop completely by modifying desktop's view by creating a "ViewRedirect" automation hook. Check https://developer.hubleto.com/v0/advanced-development/hooks for mor information about hooks.
michal-barnas Maybe it would be also great to implement a theme import function, where one could simply get and import a css file, which would get applied on top of the system styles.
hubleto-community You can write your own theme, put it into assets/css/themes/your_theme.css Then you'll be able to activate it in Maintenance -> Settings -> Change theme
