Can i integrate vaadin lumo theme for cuba application?
Unfortunately, you cannot integrate LUMO theme, since it is compatible only with Vaadin 10. Theme is not only colors and gradients, it includes a lot of CSS for concrete UI components.
You can only emulate LUMO fonts, colors, sizing, spacing borders and shadows using theme extension.
At first, we are planning to introduce LUMO for Polymer client. It will be updated to the latest versions of Vaadin elements which can be easily customized and support the LUMO theme. See also Roadmap for version 6.10 - CUBA.Platform