diff --git a/htdocs/theme/eldy/style.css.php b/htdocs/theme/eldy/style.css.php
index 1f58937d879..35f6f56c57c 100644
--- a/htdocs/theme/eldy/style.css.php
+++ b/htdocs/theme/eldy/style.css.php
@@ -61,7 +61,7 @@ if (defined('THEME_ONLY_CONSTANT')) return;
 
 session_cache_limiter('public');
 
-require_once '../../main.inc.php';
+require_once __DIR__.'/../../main.inc.php'; // __DIR__ allow this script to be included in custom themes
 require_once DOL_DOCUMENT_ROOT.'/core/lib/functions2.lib.php';
 
 // Load user to have $user->conf loaded (not done into main because of NOLOGIN constant defined)