Merge pull request #979 from ckeditor/new-apporach-for-splitting-css-…

…into-editor-and-content-stylsheets

Fix (build-tools): Should preserved all needed selectors and at-rules in CSS files after split into editor and content stylesheets. Closes ckeditor/ckeditor5#16703.

packages/ckeditor5-dev-build-tools/package.json

@@ -27,6 +27,7 @@
     "ckeditor5-dev-build-tools": "bin/build-project.js"
   },
   "dependencies": {
+    "@fullhuman/postcss-purgecss": "^6.0.0",
     "@rollup/plugin-commonjs": "^25.0.7",
     "@rollup/plugin-json": "^6.1.0",
     "@rollup/plugin-node-resolve": "^15.2.3",
@@ -36,8 +37,8 @@
     "@rollup/pluginutils": "^5.1.0",
     "@swc/core": "^1.4.8",
     "chalk": "^5.3.0",
-    "css": "^3.0.0",
-    "cssnano": "^6.0.3",
+    "cssnano": "^7.0.4",
+    "cssnano-preset-lite": "^4.0.1",
     "estree-walker": "^3.0.3",
     "glob": "^10.3.10",
     "lodash-es": "^4.17.21",

packages/ckeditor5-dev-build-tools/src/config.ts

@@ -145,7 +145,7 @@ export async function getRollupConfig( options: BuildOptions ) {
 			} ),
 
 			/**
-			 * Allows using imports, mixins and nesting in CSS and exctacts output CSS to a separate file.
+			 * Allows using imports, mixins and nesting in CSS and extracts output CSS to a separate file.
 			 */
 			styles( {
 				mode: [ 'extract', cssFileName ],