diff --git a/static/js/app.js b/static/js/app.js
index 83c238e..868dd26 100644
--- a/static/js/app.js
+++ b/static/js/app.js
@@ -3712,6 +3712,9 @@ async function applyPdfZoom(newZoom) {
     pdfSmartZoomPage(pdfCurrentPage);
   } else {
     await reRenderPdf();
+    // Wait for two animation frames so the browser finishes layout
+    // before reading scrollHeight for position restoration
+    await new Promise(r => requestAnimationFrame(() => requestAnimationFrame(r)));
     if (contentEl2 && fraction > 0) {
       contentEl2.scrollTop = fraction * (contentEl2.scrollHeight - contentEl2.clientHeight);
     }
@@ -3722,7 +3725,13 @@ async function reRenderPdf() {
   if (!currentPdfBuffer) return;
   const contentEl = $('reader-content');
   if (!contentEl) return;
+  const overlay = $('reader-overlay');
+  const loadingEl = document.createElement('div');
+  loadingEl.className = 'pdf-loading-overlay';
+  loadingEl.innerHTML = '<span class="pdf-loading-spinner"></span>';
+  if (overlay) overlay.appendChild(loadingEl);
   await renderPdf(currentPdfBuffer, contentEl);
+  loadingEl.remove();
   if (readerSettings.pdfPaginated) enterPdfPaginatedMode();
 }