fix: stylesheet separatore pannello admin

src/assets/style.css

@@ -256,6 +256,15 @@ form button:hover {
     padding: 20px;
 }
 
+.admin-divider{
+    display: block;
+    height: 1px;
+    border: 0;
+    border-top: 1px solid #ddd;
+    margin: 1em 0;
+    padding: 0;
+}
+
 .admin-stats-grid {
     display: grid;
     grid-template-columns: repeat(auto-fit, minmax(180px, 1fr));