fix VoiceOver by making hidden panes display: none

script/run.ts

@@ -261,8 +261,19 @@ namespace Flat {
 export function fadeTo(newPane: Pane): void {
   for (const pane of allPanes) {
     const here = pane == newPane;
-    document.getElementById(pane)!.dataset.selected = `${here}`;
-    if (here) { history.replaceState(null, '🦎', `#${pane}`); }
+    const elem = document.getElementById(pane)!;
+    if (here) {
+      elem.style.display = 'unset';
+      setTimeout(() => {
+        elem.dataset.selected = 'true';
+        history.replaceState(null, '🦎', `#${pane}`);
+      });
+    } else if (elem.dataset.selected == 'true') {
+      elem.addEventListener('transitionend',
+                            () => elem.style.display = 'none',
+                            {once: true});
+      elem.dataset.selected = 'false';
+    }
   }
 }
 
@@ -294,6 +305,10 @@ function setup(): void {
       Cube.instantMoveTo(pane);
       Flat.fadeTo(pane);
       box.checked = true;
+    } else {
+      const elem = document.getElementById(pane)!;
+      elem.dataset.selected = 'false';
+      elem.style.display = 'none';
     }
   }
 }