diff --git a/classes/controller/AdminController.php b/classes/controller/AdminController.php
index 6acb4f6f3..57d33d40d 100644
--- a/classes/controller/AdminController.php
+++ b/classes/controller/AdminController.php
@@ -1582,7 +1582,9 @@ class AdminControllerCore extends Controller
 	public function setMedia()
 	{
 		$this->addCSS(_PS_CSS_DIR_.'admin.css', 'all');
-		$this->addCSS(__PS_BASE_URI__.str_ireplace(_PS_ROOT_DIR_.DIRECTORY_SEPARATOR, '', _PS_ADMIN_DIR_).'/themes/'.$this->bo_theme.'/css/admin.css', 'all');
+		$admin_webpath = str_ireplace(_PS_ROOT_DIR_, '', _PS_ADMIN_DIR_);
+		$admin_webpath = preg_replace('/^'.preg_quote(DIRECTORY_SEPARATOR, '/').'/', '', $admin_webpath);
+		$this->addCSS(__PS_BASE_URI__.$admin_webpath.'/themes/'.$this->bo_theme.'/css/admin.css', 'all');
 		if ($this->context->language->is_rtl)
 			$this->addCSS(_THEME_CSS_DIR_.'rtl.css');