rotate triangle icon

packages/app/src/components/Sidebar/PageTree/Item.tsx

@@ -177,7 +177,7 @@ const Item: FC<ItemProps> = (props: ItemProps) => {
   const opacityStyle = { opacity: 1.0 };
   if (page.isTarget) opacityStyle.opacity = 0.7;
 
-  const buttonClass = isOpen ? 'rotate' : '';
+  const buttonClass = isOpen ? 'rotate' : 'hoge';
 
   return (
     <div className="grw-pagetree-item-wrapper">

packages/app/src/styles/_page-tree.scss

@@ -21,8 +21,13 @@
       background-color: transparent;
 
       &.rotate {
+        transition: 0.5s;
         transform: rotate(90deg);
       }
+      &.hoge {
+        transition: 0.5s;
+        transform: rotate(0deg);
+      }
     }
 
     .grw-pagetree-title-anchor {