There are some Silverlight diehards, like me, who still mourn the death of the technology at the hands of a parent who suddenly didn't love it. This sudden change of heart was because it didn't fit with the crazy new direction Windows was headed off in and because office politics said so.
If you knew Silverlight then you will probably think of it as a good system. If you didn't know Silverlight then you most probably join in with the herd and say how pleased you are that a proprietary solution went down the pan and good riddance.
Now there is Fayde.Well to be honest Fayde has been around a while, but it has now reached a level of maturity that deserves your attention if you miss Silverlight.
The programming language is TypeScript and the XAMLis rendered onto a Canvas object where all of the UI is implemented. What this means is that Fayde replaces HTML/CSS and eliminates browser inconsistencies with XAML rendered controls in the Canvas object. In short, as long as the browser supports Canvas it all works. This means you can also deploy it to a desktop using node-webkit.
One thing Fayde does prove is how weak and useless our current HTML as programming platform is.
Currently it has all the Silverlight core controls, styles, templates and data binding. It also has some new controls and over time Fayde will become a superset of the Silverlight approach.
If you want to join the project you can as it is open source and on GitHub. You can create new controls using TypeScript - basically just render your control to Canvas.
In fact documentation is something the project lacks. There is no hiding the fact that you are going to have to port your C# to TypeScript and there are lots of things away from the UI that you will discover you cannot port easily, or perhaps at all. The project is working on libraries for LINQ and WFC.
This is really a XAML rendering engine with support for the main principles of the Silverlight UI, mostly data binding.
This said, if you are looking to continue using a Silverlight approach to apps and are prepared to do some conversion Fayde could be the solution you are looking for. Given it is open source, you can be sure that it wont be nuked in some internal office politics.