initial working version

inc/Dependencies/Minify/Minify.php

@@ -105,7 +105,7 @@ public function add($data /* $data = null, ... */)
 	 * @param string|string[] $data
 	 *
 	 * @return static
-	 * 
+	 *
 	 * @throws IOException
 	 */
 	public function addFile($data /* $data = null, ... */)
@@ -137,6 +137,10 @@ public function addFile($data /* $data = null, ... */)
 		return $this;
 	}
 
+	public function addData( $path, $content ) {
+		$this->data[ $path ] = $content;
+	}
+
 	/**
 	 * Minify the data & (optionally) saves it to a file.
 	 *

inc/Engine/Optimization/CSSTrait.php

@@ -107,28 +107,6 @@ protected function move( ConverterInterface $converter, $content, $source ) {
 			\)
 
 			/ix',
-
-			// @import "xxx"
-			'/
-			# import statement
-			@import
-
-			# whitespace
-			\s+
-
-				# we don\'t have to check for @import url(), because the
-				# condition above will already catch these
-
-				# open path enclosure
-				(?P<quotes>["\'])
-
-					# fetch path
-					(?P<path>.+?)
-
-				# close path enclosure
-				(?P=quotes)
-
-			/ix',
 		];
 
 		// find all relative urls in css.

inc/Engine/Optimization/Minify/CSS/Minify.php

@@ -310,7 +310,8 @@ protected function font_display_swap( $url, $minified_file, $content ) {
 	 */
 	protected function minify( $file_path, $minified_file, $file_content ) {
 		$file_content     = $this->rewrite_paths( $file_path, $minified_file, $file_content );
-		$minifier         = $this->get_minifier( $file_content );
+		$minifier         = $this->get_minifier();
+		$minifier->addData( $file_path, $file_content );
 		$minified_content = $minifier->minify();
 
 		if ( empty( $minified_content ) ) {
@@ -337,7 +338,7 @@ protected function minify( $file_path, $minified_file, $file_content ) {
 	 *
 	 * @return Minifier\CSS
 	 */
-	protected function get_minifier( $file_content ) {
-		return new Minifier\CSS( $file_content );
+	protected function get_minifier() {
+		return new Minifier\CSS();
 	}
 }