adjust z-index

src/client/styles/scss/_layout.scss

@@ -35,6 +35,11 @@
     top: calc(50vh - 20px);
   }
 
+  div[class$='-NavigationContainer'] {
+    // Adjust to be on top of the growi subnavigation
+    z-index: $zindex-sticky + 5;
+  }
+
   div[class$='-Outer'] {
     div[class$='-Shadow'] {
       background: unset;

src/client/styles/scss/_subnav.scss

@@ -12,7 +12,8 @@ header.grw-header {
   top: $grw-navbar-height;
 
   // Adjust to be on top of the growi subnavigation
-  z-index: $zindex-sticky - 100;
+  z-index: $zindex-sticky;
+
   height: 80px;
   pointer-events: none; // disable pointer events for sticky