fix empty.css path

empty.html

@@ -6,7 +6,7 @@
     <title></title>
     <meta name="description" content="">
     <meta name="viewport" content="width=device-width, initial-scale=1">
-    <link rel="stylesheet" href="css/empty.css">
+    <link rel="stylesheet" href="assets/css/empty.css">
 		<style>
 		.ok-vegane { color: green; }
 		.pas-vegane { color: red; font-weight: bold; }