diff --git a/CHANGELOG.md b/CHANGELOG.md
index ca72b3a..5a98f87 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -14,6 +14,10 @@ No unreleased changes.
 
 - Added `AbstractTestCase::getFixtureContents()`, which returns the contents of a fixture file.
 
+### Changed
+
+- Simplified some code.
+
 ### Fixed
 
 - Got `AbstractTestCaseTest` working 🤦‍♂️
diff --git a/src/CssMinifier.php b/src/CssMinifier.php
index 18394d6..502640a 100644
--- a/src/CssMinifier.php
+++ b/src/CssMinifier.php
@@ -43,7 +43,8 @@ private function replace(
     public function removeSuperfluousWhitespaceFilter(string $css): string
     {
         // Normalize newlines.
-        $css = str_replace(["\r\n", "\r", "\n"], "\n", $css);
+        /** @var string */
+        $css = preg_replace('~\R~', "\n", $css);
 
         // Normalize horizontal whitespace.
         $css = str_replace("\t", ' ', $css);