Robin Malfait 3c937ecee7
Inject polyfills after @import and body-less @layer (#17493)
This PR fixes an issue where polyfills were injected at the top, but
they should be after `@import` and body-less `@layer` rules.

This is necessary in case you are using Google fonts like this for
example:
```css
@import url('https://fonts.google.com');
@import "tailwindcss";
```

While the `@import url(…);` sits above `@import "tailwindcss";` in the
final generated CSS we injected the polyfills at the very beginning.

This PR will inject the polyfills after the first AST Node that is not:
1. A comment
2. An external import — `@import url(…)`
3. A body-less layer — `@layer foo, bar, baz;`

The snapshots look a little confusing, but that's because Lightning CSS
is optimizing the output and moving things around a bit:

<img width="1482" alt="image"
src="https://github.com/user-attachments/assets/a0552c8b-93df-4e1d-ad90-8b8abf9492b1"
/>

[Lightning CSS
Playground](https://lightningcss.dev/playground/index.html#%7B%22minify%22%3Afalse%2C%22customMedia%22%3Atrue%2C%22cssModules%22%3Afalse%2C%22analyzeDependencies%22%3Afalse%2C%22targets%22%3A%7B%22chrome%22%3A6225920%7D%2C%22include%22%3A0%2C%22exclude%22%3A0%2C%22source%22%3A%22%40layer%20theme%2C%20base%2C%20components%2C%20utilities%3B%5Cn%5Cn%40supports%20(((-webkit-hyphens%3A%20none))%20and%20(not%20(margin-trim%3A%20inline)))%20or%20((-moz-orient%3A%20inline)%20and%20(not%20(color%3A%20rgb(from%20red%20r%20g%20b))))%20%7B%5Cn%20%20%40layer%20base%20%7B%5Cn%20%20%20%20*%2C%20%3Abefore%2C%20%3Aafter%2C%20%3A%3Abackdrop%20%7B%5Cn%20%20%20%20%20%20--tw-font-weight%3A%20initial%3B%5Cn%20%20%20%20%7D%5Cn%20%20%7D%5Cn%7D%5Cn%5Cn%40layer%20theme%20%7B%5Cn%20%20%3Aroot%2C%20%3Ahost%20%7B%5Cn%20%20%20%20--font-sans%3A%20ui-sans-serif%2C%20system-ui%2C%20sans-serif%2C%20%5C%22Apple%20Color%20Emoji%5C%22%2C%20%5C%22Segoe%20UI%20Emoji%5C%22%2C%20%5C%22Segoe%20UI%20Symbol%5C%22%2C%20%5C%22Noto%20Color%20Emoji%5C%22%3B%5Cn%20%20%20%20--font-mono%3A%20ui-monospace%2C%20SFMono-Regular%2C%20Menlo%2C%20Monaco%2C%20Consolas%2C%20%5C%22Liberation%20Mono%5C%22%2C%20%5C%22Courier%20New%5C%22%2C%20monospace%3B%5Cn%20%20%20%5Cn%20%20%7D%5Cn%7D%5Cn%5Cn%40layer%20base%20%7B%5Cn%20%20*%2C%20%3Aafter%2C%20%3Abefore%2C%20%3A%3Abackdrop%20%7B%5Cn%20%20%20%20box-sizing%3A%20border-box%3B%5Cn%20%20%20%20border%3A%200%20solid%3B%5Cn%20%20%20%20margin%3A%200%3B%5Cn%20%20%20%20padding%3A%200%3B%5Cn%20%20%7D%5Cn%7D%5Cn%5Cn%40layer%20utilities%20%7B%5Cn%20%20.text-2xl%20%7B%5Cn%20%20%20%20font-size%3A%20var(--text-2xl)%3B%5Cn%20%20%20%20line-height%3A%20var(--tw-leading%2C%20var(--text-2xl--line-height))%3B%5Cn%20%20%7D%5Cn%7D%5Cn%5Cn%40property%20--tw-font-weight%20%7B%5Cn%20%20syntax%3A%20%5C%22*%5C%22%3B%5Cn%20%20inherits%3A%20false%5Cn%7D%22%2C%22visitorEnabled%22%3Afalse%2C%22visitor%22%3A%22%7B%5Cn%20%20Color(color)%20%7B%5Cn%20%20%20%20if%20(color.type%20%3D%3D%3D%20'rgb')%20%7B%5Cn%20%20%20%20%20%20color.g%20%3D%200%3B%5Cn%20%20%20%20%20%20return%20color%3B%5Cn%20%20%20%20%7D%5Cn%20%20%7D%5Cn%7D%22%2C%22unusedSymbols%22%3A%5B%5D%2C%22version%22%3A%22local%22%7D)

Fixes: #17494
2025-04-02 11:05:35 +02:00
..