[bugfix] make sure previous card is not shown in modal by defaulting to "loading..."

src/assets/js/main.js

@@ -4,6 +4,7 @@ window.bootstrap = bootstrap;
 
 // trap browser back and close the modal if open
 const cardModal = document.getElementById('cardModal');
+const loadingMsg = cardModal.innerHTML;
 // Push a new history state when the modal is shown
 cardModal.addEventListener('shown.bs.modal', () => {
   history.pushState({ modalOpen: true }, null, '#cardModal');
@@ -19,6 +20,7 @@ window.addEventListener('popstate', (e) => {
 });
 // Trigger a back navigation when the modal is closed via its native controls (X, backdrop click)
 cardModal.addEventListener('hide.bs.modal', () => {
+  cardModal.innerHTML = loadingMsg;
   if (history.state && history.state.modalOpen) {
     history.back();
   }