Scoped global styling not working

[pikeas]

Describe the bug
Scoped global styling doesn't seem to work. Classes are being applied and the component is reactive, so the issue is specifically around style scoping.

To Reproduce

<script lang="ts">
    import MyComponent from "$lib/things/MyComponent.svelte"
</script>

<section>
    <MyComponent />
</section>

MyComponent is exactly copied from https://svelte-headlessui.goss.io/docs/general-concepts#the-global-modifier, the version using a wrapper div and * > :global(.checked).

[pikeas]

I just sanity checked this with dummy components:

<script lang="ts">
    import Outer from "$lib/foo/Outer.svelte"
</script>

<Outer />

<script lang="ts">
    import Inner from "./Inner.svelte"
</script>

<div>Outer 1</div>
<div><Inner foo="inner" /></div>
<div>Outer 2</div>

<style>
    * > :global(.inner) {
        color: red;
    }
</style>

<script lang="ts">
    export let foo = ""
</script>

<div class={foo}>Inner</div>

This works as expected so svelte-headlessui is doing something funky. Maybe related to using class as the prop name?

[pikeas]

The plot thickens!

For RadioGroup:

• * > :global(label) does not work
• * :global(label) works

For Dialog:

• * > :global(h2) does not work
• * :global(h2) also does not work!

Ah, just found this docs note:

This rule won’t work properly inside a portal, which means that it won’t work properly for a <Dialog>. To style the <Dialog>, you will need to either 1) use global styles without the * > scoping, 2) put a wrapper element inside the <Dialog> and style that instead, or 3) use one of the other styling approaches.

I think that explains everything I've seen. Definitely surprising!

I'll keep this open for the RadioGroup behavior - should this work with and without the descendant selector?