I just want to point out there is a great alternative from Microsoft called `fast-design`[0] which provides a more fleshed out experience than Lit does, in terms of out of the box components.
It does have lower level packages if you don't want ready made components too
FAST is kind of like a Lit-clone (though it patches global prototypes) plus a design system base.
There are lots of design systems built with Lit that you can chose from instead of us including our own: Shoelace, Adobe Spectrum, Redhat Patternfly, IBM Carbon, Material Web Components and more.
It does have lower level packages if you don't want ready made components too
[0]: https://www.fast.design/