diff --git a/lib/inliner.php b/lib/inliner.php
index 8d5355a..f1ecbb8 100644
--- a/lib/inliner.php
+++ b/lib/inliner.php
@@ -12,14 +12,30 @@ function inlineLocalStylesFromHref($inputString) {
         // Get the content of the local CSS file
         $cssContent = file_get_contents($_SERVER['DOCUMENT_ROOT'] . '/' . $href);
 
-        // Create an inline style tag with the CSS content
+        // Replace url() declarations in the CSS content with inline data
+        $cssContent = preg_replace_callback('/url\(["\']?(\/.*?)["\']?\)/i', function($urlMatch) {
+            // Extract the URL value
+            $url = $urlMatch[1];
+
+            // Get the content of the external file specified in the url()
+            $fileContent = file_get_contents($_SERVER['DOCUMENT_ROOT'] . $url);
+
+            // Base64 encode the content for inline use
+            $base64Content = base64_encode($fileContent);
+
+            // Create the inline data URI
+            $dataUri = 'url("data:image/' . pathinfo($url, PATHINFO_EXTENSION) . ';base64,' . $base64Content . '")';
+
+            return $dataUri;
+        }, $cssContent);
+
+        // Create an inline style tag with the modified CSS content
         return "<style>\n{$cssContent}\n</style>";
     }, $inputString);
 
     return $outputString;
 }
 
-
 function inlineScriptFromSrc($inputString) {
     // Define the regular expression pattern to match <script> tags with src attribute
     $pattern = '/<script.*?src=["\']\/(.*?)["\'].*?>\s*<\/script>/i';