[FEATURE] Do not escape characters that do not need escaping in CSS string

Author: 8ctopus

src/Value/CSSString.php

@@ -97,28 +97,10 @@ public function render(OutputFormat $outputFormat): string
 
     private function escape(string $str, string $quote) : string
     {
-        $matches = [
-            0x0, // null
-            0x5c, // \
-        ];
+        $str = \addslashes($str);
 
-        $matches[] = $quote === '"' ? 0x22 : 0x27;
+        $replace = $quote === '"' ? ["\\'" => "'"] : ["\\\"" => "\""];
 
-        $length = \strlen($str);
-        $output = '';
-        $previous = 0x0;
-
-        for ($i = 0; $i < $length; ++$i) {
-            $current = \ord($str[$i]);
-
-            if (\in_array($current, $matches, true) && $previous !== 0x5c) {
-                $output .= '\\';
-            }
-
-            $output .= $str[$i];
-            $previous = $current;
-        }
-
-        return $output;
+        return \str_replace(array_keys($replace), array_values($replace), $str);
     }
 }