diff --git a/frontend/js/ambient.js b/frontend/js/ambient.js
index 586235ea..631f382c 100644
--- a/frontend/js/ambient.js
+++ b/frontend/js/ambient.js
@@ -489,7 +489,7 @@ document.addEventListener('DOMContentLoaded', () => {
 
     const type = Math.random();
     if (type < 0.5) {
-      el.innerHTML = `<svg width="${size}" height="${size}" viewBox="0 0 20 20">
+      el.textContent = `<svg width="${size}" height="${size}" viewBox="0 0 20 20">
         <path d="M10 1 L11.5 8.5 L19 10 L11.5 11.5 L10 19 L8.5 11.5 L1 10 L8.5 8.5 Z"
           fill="${color}" opacity="0.9"/></svg>`;
     } else if (type < 0.75) {
diff --git a/frontend/js/app.js b/frontend/js/app.js
index 36a0fdef..55d32b43 100644
--- a/frontend/js/app.js
+++ b/frontend/js/app.js
@@ -152,7 +152,7 @@ const CollectionAPI = {
             method: 'POST',
             headers: this.getHeaders(),
             credentials: 'include',
-            body: JSON.stringify({ user_id: parseInt(userId), name, description, is_public: isPublic })
+            body: JSON.stringify({ user_id: parseInt(userId, 10), name, description, is_public: isPublic })
         });
         if (!res.ok) {
             const errData = await res.json().catch(() => ({}));
diff --git a/frontend/js/library-3d.js b/frontend/js/library-3d.js
index ba5cc1c6..c6461afc 100644
--- a/frontend/js/library-3d.js
+++ b/frontend/js/library-3d.js
@@ -2407,7 +2407,7 @@ class BookshelfRenderer3D {
                     if (progressBadge) progressBadge.textContent = `${clamped}% `;
                     // Sync pages input
                     if (pagesReadInput && pagesTotalInput) {
-                        const pages = Math.round((clamped / 100) * parseInt(pagesTotalInput.value || totalPages));
+                        const pages = Math.round((clamped / 100) * parseInt(pagesTotalInput.value || totalPages, 10));
                         pagesReadInput.value = pages;
                     }
                     if (pagesBar) pagesBar.style.width = `${clamped}% `;