Since Sciter was mentioned, I'll probably mention https://github.com/zserge/webview which is a thin wrapper over native browser engines (webviews) and allows to bind HTML/CSS UI to the native code. It results in fairly small executables, and works well with C/C++/Go or there are some 3rd-party Rust or Nim bindings.

The big problem with that is that you end up using different browsers on different platforms (IE10/11 for Windows, webkit for Linux and MAC) which is a bit problematic to support.

LCUI doesn't seem to rely on a specific browser but still remains fairly small so that seems pretty good.

To be fair, it's not that bad (I have made a couple of apps based on the webview) - IE11 is a rather decent browser supporting all the niceties from CSS3, flexbox etc. It's not that different from making layouts for web pages, when you have to support IE11 anyway. All the IE11 pitfalls are covered on stackoverflow, so it didn't feel like wasting much time to make windows version of the app look exactly like linux or macOS.

But small means less features, such as: unsupport rounded border, transitions, animations, etc.

Is it on maven central?

I've just published the release today, it should be available within the next few hours. Meanwhile you can build it from the github sources.

It should be available as:

    <dependency>
        <groupId>co.trikita</groupId>
        <artifactId>anvil</artifactId>
        <version>0.0.2</version>
    </dependency>

Gradle:

    compile 'co.trikita:anvil:0.0.2'

What about an attributes without namespace like: style="?android:attr/starStyle" ?

Good question. Now I use "android:" namespace by default (if no other namespace was given). So, for custom namespaces you write "mynamespace:foo", for android namespace - just "foo". I've just updated AAML to use prefix "=:foo" for default namespace or no namespace. If you prefer other syntax for empty namespace - you are welcome to suggest!