tidy cache display

index.html

@@ -87,8 +87,11 @@
                 <div id="storage-details">
                 </div>
                 <div id="cache-details">
+                <details>
+                <summary></summary>
                 <ul>
                 </ul>
+                </details>
                 </div>
             </div>
             <div id="review-overlay" class="fullscreen-overlay">

js/main.js

@@ -221,9 +221,9 @@ async function loadExamList(data) {
   // Check the database for exams that have been saved
   question_db.saved_exams.toArray().then((saved_exams) => {
     if (saved_exams.length < 1) {
-      $("#cache-details ul").append("<span>No cached exams / questions</span>");
+      $("#cache-details summary").append("<span>No cached exams / questions</span>");
     } else {
-      $("#cache-details ul").append("<span>Cached exams / questions:</span>");
+      $("#cache-details summary").append("<span>Cached exams / questions:</span>");
     }
     saved_exams.forEach((saved_exam, n) => {
       $("#cache-details ul").append(