Docs: add warning callout for Yarn Berry #25933

	name: CSS

	on:
	push:
	branches:
	- main
	pull_request:
	workflow_dispatch:

	env:
	FORCE_COLOR: 2
	NODE: 20

	permissions:
	contents: read

	jobs:
	css:
	runs-on: ubuntu-latest

	steps:
	- name: Clone repository
	uses: actions/checkout@v4
	with:
	persist-credentials: false

	- name: Set up Node.js
	uses: actions/setup-node@v4
	with:
	node-version: "${{ env.NODE }}"
	cache: npm

	- name: Install npm dependencies
	run: npm ci

	- name: Build CSS
	run: npm run css

	- name: Run CSS tests
	run: npm run css-test

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