[sli]

That's not much different from a React app, in terms of how much HTML needs to be involved. As low as 9 lines, if you want (basic HTML scaffold + root element).

I'd think a particularly adventurous person could do it without writing any HTML and just create the scaffolding directly in the DOM before the app is mounted, but that would be a little silly.

[jdemler]

But the story inside the app is different:

React (at least as I understand it): The app emits HTML and CSS you wrote

Elm + style-elements: The app emits HTML and CSS you described

[beefalo]

You aren't writing HTML in React and there are a number of libraries to replace writing CSS