[c-smile]

I think that still nothing can match Sciter's style sets feature.

JS (mycomponent.js):

    export function MyComponent() {

      return <div styleset={__DIR__ + "components.css#my-component"}>
         <header>Hi!</header>
         ...
      </div>; 

    }

CSS (components.css) :

    @set my-component {

      :root { background:red; } /* the component itself */

      :root > header { background:gold; } /* its content */
      :root > footer { background:var(footerColor,#0F0); } /* use of vars that can be set in JS too */
    }