diff --git a/composer.json b/composer.json
index c228f382..0f0384ba 100644
--- a/composer.json
+++ b/composer.json
@@ -25,7 +25,8 @@
     "ipl/orm": ">=0.5.2",
     "ipl/scheduler": ">=0.1.0",
     "ipl/stdlib": ">=0.12.0",
-    "fortawesome/font-awesome": "^6"
+    "fortawesome/font-awesome": "^6",
+    "wikimedia/less.php": "^3.2.1"
   },
   "require-dev": {
     "ipl/html": "dev-main",
diff --git a/src/LessRuleset.php b/src/LessRuleset.php
index 3a55825f..2e30a4b4 100644
--- a/src/LessRuleset.php
+++ b/src/LessRuleset.php
@@ -3,7 +3,7 @@
 namespace ipl\Web;
 
 use ArrayObject;
-use Icinga\Util\LessParser;
+use Less_Parser;
 
 /**
  * @extends ArrayObject<string, string>
@@ -144,10 +144,10 @@ public function addRuleset(LessRuleset $ruleset): self
      */
     public function renderCss(): string
     {
-        $lessc = new LessParser();
-        $lessc->setFormatter('compressed');
+        $parser = new Less_Parser(['compress' => true]);
+        $parser->parse($this->renderLess());
 
-        return $lessc->compile($this->renderLess());
+        return $parser->getCss();
     }
 
     /**