diff --git a/css/leptonChrome.css b/css/leptonChrome.css
index 78ab784..2312931 100644
--- a/css/leptonChrome.css
+++ b/css/leptonChrome.css
@@ -8182,7 +8182,7 @@
     :root:has(#sidebar-box[hidden="true"]) #nav-bar {
       margin-inline-start: var(--uc-sidebar-activate-width-reverse) !important;
       opacity: 0;
-      visibility: collapse;
+      visibility: hidden;
     }
 
     :root:has(#sidebar-box[positionend="true"]) #nav-bar {
diff --git a/src/navbar/_as_sidebar.scss b/src/navbar/_as_sidebar.scss
index 7191049..8b0f1fb 100644
--- a/src/navbar/_as_sidebar.scss
+++ b/src/navbar/_as_sidebar.scss
@@ -36,7 +36,7 @@
   :root:has(#sidebar-box[hidden="true"]) #nav-bar {
     margin-inline-start: var(--uc-sidebar-activate-width-reverse) !important;
     opacity: 0;
-    visibility: collapse;
+    visibility: hidden; // If use `collapse`, inline `--urlbar-toolbar-height` variable is calculated strangely small.
   }
   :root:has(#sidebar-box[positionend="true"]) #nav-bar {
     right: 0;
@@ -122,4 +122,3 @@
     flex-shrink: 0.5 !important;
   }
 }
-