Veautiful is a reactive web UI toolkit written in Scala. It combines low level control with high level ease of use.
It was developed for use in creating interactive Open Educational Resources (OERs), as materials in education sometimes need lots of different kind of demo, sim, and explorable explanation.
As I develop it for use in outreach sites, OERs, presentations and other materials, it has an update cycle that goes through patches of updates well spread apart.
Doctacular, contained within the same GitHub repository, is a suite of components to help makes building OERs, talks, and tutorials easy. It contains components for interactive presentation decks, interactive tutorials, and websites.
The guiding principle is that you own the design of your code; the framework doesn't. Scala is a mixed paradigm language; this is a mixed paradigm UI framework.
Rather than force you to play the way the framework wants you to play, it'll give you a bunch of components and node types that compose fairly neatly, and each have low conceptual overhead.
All going well, it shouldn't feel "revolutionary", but small and straightforward, while letting you build UIs with very little code.