improve barcode preview

css/code.css

@@ -7,6 +7,10 @@ details svg, details img {
 .row-cols-lg-2:has(.bg-azure) {
   justify-content: center;
 }
+.card-img-top {
+    width: 90%;
+    margin: 5%;
+}
 table td, table th {
    padding-left: 5px;
    padding-right: 5px;