fix(sidebar): prevent duplicate sidebar components on tablet in grid mode

In tablet grid layout, the flat flex-row styles for sidebar components
were applying 'display: contents' to ALL .sidebar-content containers,
including the desktop-only ones (hidden lg:flex). This caused both the
tablet-specific and desktop-specific sidebar containers to be flattened
into the bottom bar simultaneously, resulting in duplicate components.

The fix narrows the CSS selector to only target tablet-specific
containers by adding the .lg\:hidden class, which is present on tablet
containers but absent from desktop containers.

Author: matsuzaka-yuki

src/styles/banner.css

@@ -553,7 +553,8 @@ body.wallpaper-transparent #toc-inner-wrapper:has(table-of-contents[data-loaded=
 
   #main-grid[data-layout-mode="grid"] #sidebar > div,
   #main-grid[data-layout-mode="grid"] #sidebar #sidebar-sticky,
-  #main-grid[data-layout-mode="grid"] #sidebar .sidebar-content {
+  /* 仅扁平化平板专用的 .sidebar-content（带 lg:hidden 的容器），避免桌面容器在平板端被强制显示 */
+  #main-grid[data-layout-mode="grid"] #sidebar .sidebar-content.lg\:hidden {
     display: contents !important;
     margin: 0 !important;
     padding: 0 !important;