fix executor

Author: GoodDayForSurf

packages/devextreme-themebuilder/src/modules/post-compiler.ts

@@ -13,7 +13,7 @@ export function addBasePath(css: string | Buffer, basePath: string): string {
 export function addInfoHeader(
   css: string | Buffer,
   version: string,
-  placeHeaderBeforeCharset = false,
+  preserveCharsetBoundary = false,
 ): string {
   const generatedBy = '* Generated by the DevExpress ThemeBuilder';
   const versionString = `* Version: ${version}`;
@@ -24,14 +24,16 @@ export function addInfoHeader(
   const encoding = '@charset "UTF-8";';
 
   // clean-css may emit @charset immediately followed by :root / @import with no newline.
-  // Keep backward-compatible output by default (charset + header), and allow parity mode
-  // for compile pipeline where header should be before @charset.
+  // Keep backward-compatible output by default (charset + header). In parity mode keep
+  // @charset as the very first statement and move the info header to the end, so:
+  // 1) charset decoding stays correct in browsers
+  // 2) normalized comparison keeps '\n' between @charset and next rule.
   const charsetPrefix = /^@charset\s+"utf-8";\s*/i;
   const match = source.match(charsetPrefix);
   if (match) {
     const rest = source.slice(match[0].length).replace(/^\s*/, '');
-    return placeHeaderBeforeCharset
-      ? `${header}${encoding}\n${rest}`
+    return preserveCharsetBoundary
+      ? `${encoding}\n${rest}\n${header}`
       : `${encoding}\n${header}${rest}`;
   }
   return `${header}${source}`;