Lit: a library for building fast, lightweight web components

I'm all for a lightweight approach to software development. But I don't understand the concept here.

Looking at the first example:

First I had to switch it from TS to JS. As I don't consider something that needs compilation before it runs to be lightweight.

Then, the first line is:

    import {html, css, LitElement} from 'lit';

What is this? This is not a valid import. At least not in the browser. Is the example something that you have to compile on the server to make it run in the browser?

And when I use the "download" button on the playground version of the first example, I get a "package.json" which defines dependencies. That is also certainly not something a browser can handle.

So do I assume correctly that I need to set up a webserver, a dependency manager, and a serverside runtime to use these "light weight" components?

Or am I missing something? What would be the minimal amount of steps to save the example and actually have it run in the browser?