This idea is a suggestion for OutSystems UI but also for an improvement on Service Studio.

• Add support for a dark theme in OutSystemsUI.
  • This version of the theme would be similar to the viewport simulation approach, with classes in the body tag displaying which type of device the user has. The new classes would be "dark" and "light".
• Add a ThemeSwitcher Pattern to OutSystemsUI.
  • This pattern would be responsible for managing the theme, keeping the user's preference in local storage/client variables.
• Add a dark theme simulation in Service Studio
  • Again, similar to the viewport simulation that lets the developer see the page in 3 different screen sizes, there would be an option to see the page in dark or light mode.

The dark theme is a great modern addition to any app, because it lets users choose which theme is best for their condition. Having it integrated both in OutSystemsUI and ServiceCenter would allow OutSystems developers to have an implementation of this feature that is both universal and officially suported.