Reproduction for postcss-cascade-layers issue

Steps to reproduce:

In a browser that supports native cascade layers:

1. npm i
2. npm run dev

Note that the button font is small. This happens because layers are working. The defaults layer has a lower priority than components, so even though the .btn styles occur lower in the import order than the css module (see App.tsx), it is overridden by the css module styling.

However, if you uncomment postcssCascadeLayers() in postcss.config.js (and then stop and restart the dev server), you'll see this is no longer the case. The .btn styles are applied, and the text size of the button is larger.