diff --git a/src/components/book/BookDesktopChapterSidebar.vue b/src/components/book/BookDesktopChapterSidebar.vue
index eb60161..fadd08a 100644
--- a/src/components/book/BookDesktopChapterSidebar.vue
+++ b/src/components/book/BookDesktopChapterSidebar.vue
@@ -140,9 +140,14 @@ defineProps<{
 
       <div
         v-if="sidebarUncategorized.length > 0"
-        class="border border-gray-200 dark:border-gray-700 rounded-lg overflow-hidden"
+        :class="chaptersByPart.parts.length > 0
+          ? 'border border-gray-200 dark:border-gray-700 rounded-lg overflow-hidden'
+          : ''"
       >
-        <div class="px-2 py-3 bg-gray-50 dark:bg-gray-700">
+        <div
+          v-if="chaptersByPart.parts.length > 0"
+          class="px-2 py-3 bg-gray-50 dark:bg-gray-700"
+        >
           <h4 class="font-medium text-gray-900 dark:text-white">Uncategorized</h4>
           <p class="text-xs text-gray-500 dark:text-gray-400 mt-1">
             {{ sidebarUncategorized.length }} chapter{{
diff --git a/src/components/book/BookMobileSection.vue b/src/components/book/BookMobileSection.vue
index c23bd3a..d0990ae 100644
--- a/src/components/book/BookMobileSection.vue
+++ b/src/components/book/BookMobileSection.vue
@@ -565,7 +565,7 @@ watch(
         </section>
 
         <section
-          v-if="chaptersByPart.uncategorized.length > 0"
+          v-if="chaptersByPart.parts.length > 0 && chaptersByPart.uncategorized.length > 0"
           class="bg-white dark:bg-gray-900 border border-gray-200 dark:border-gray-700 rounded-xl shadow-sm"
         >
           <div class="px-4 py-3 border-b border-gray-200 dark:border-gray-700 flex items-center justify-between">