use window to track scrolling for /app web routes

packages/web/components/templates/article/Article.tsx

@@ -79,6 +79,12 @@ export function Article(props: ArticleProps): JSX.Element {
           scrollContainer.scrollHeight
 
         setReadingProgress(newReadingProgress * 100)
+      } else if (window && window.document.scrollingElement) {
+        const newReadingProgress =
+          window.scrollY / window.document.scrollingElement.scrollHeight
+        const adjustedReadingProgress =
+          newReadingProgress > 0.92 ? 1 : newReadingProgress
+        setReadingProgress(adjustedReadingProgress * 100)
       }
     },
     1000

packages/web/pages/app/[username]/[slug]/index.tsx

@@ -67,9 +67,7 @@ function AppArticleEmbedContent(
   if (articleData) {
     return (
       <Box
-        ref={scrollRef}
         css={{
-          position: 'fixed',
           overflowY: 'auto',
           height: '100%',
           width: '100vw',