diff --git a/card.php b/card.php
index eba1166..e72b39e 100644
--- a/card.php
+++ b/card.php
@@ -783,7 +783,10 @@ $_GET['mainmenu'] = 'stundenzettel';
llxHeader('', $title, '', '', 0, 0, '', '', '', 'mod-stundenzettel page-card');
// Mobile CSS einbinden
-print '';
+$mobileCssFile = dol_buildpath('/stundenzettel/css/stundenzettel-mobile.css', 0);
+if (file_exists($mobileCssFile)) {
+ print '';
+}
// JavaScript für Mengenprüfung
print '