Add id=top to body and add auto scroll when details block is closed

app.js

@@ -1,10 +1,14 @@
 // Set expanded value block to a variable
 const valueBlock = document.getElementById("value-expanded");
+const bodyTop = document.getElementById("top");
 
 // Watch for the details element to be toggled
 document.querySelector('.value-block').addEventListener('toggle', function() {
   if (this.open) {
     // Scroll to contents of value block when it is opened
     valueBlock.scrollIntoView({ behavior: "smooth" });
-  }
+  } else {
+    // Scroll to top of button list when value block is closed
+    bodyTop.scrollIntoView({ behavior: "smooth" });
+ }
 });