diff --git a/desktop/scripts/check-file-sizes.mjs b/desktop/scripts/check-file-sizes.mjs
index d03e67e2b..4b994b65f 100644
--- a/desktop/scripts/check-file-sizes.mjs
+++ b/desktop/scripts/check-file-sizes.mjs
@@ -217,7 +217,11 @@ const overrides = new Map([
   // +33 for config-nudge detect-and-render + author-auth gate (normalizePubkey guard).
   ["src/shared/ui/markdown.tsx", 2152],
   ["src/shared/ui/VideoPlayer.tsx", 2199],
-  ["src/shared/ui/sidebar.tsx", 1042],
+  // +1: mobile Sidebar branch forwards the app-sidebar marker (and the rest of
+  // the container props) onto SheetContent instead of the DOM-less Sheet root,
+  // so the Buzz sidebar CSS overrides reach the portaled offcanvas sheet.
+  // Load-bearing correctness fix, not generic debt. Queued to split.
+  ["src/shared/ui/sidebar.tsx", 1043],
   // permission-outcome (fix #1381 regression): pendingPermissions state map,
   // describePermissionOutcome helper, jsonRpcId key helper (handles both
   // string and finite-number JSON-RPC ids per spec), and the acp_write
diff --git a/desktop/src/shared/styles/globals/theme.css b/desktop/src/shared/styles/globals/theme.css
index 6c9e25f55..68fd8e80b 100644
--- a/desktop/src/shared/styles/globals/theme.css
+++ b/desktop/src/shared/styles/globals/theme.css
@@ -297,6 +297,12 @@
  * the selected persona row in PersonaCatalogDialog). A root-level override
  * turned those white (white-on-white under Buzz Dark); scoping keeps them on
  * the normal accent-driven active colors.
+ *
+ * Covers the mobile/offcanvas sidebar too: `Sidebar` (shared/ui/sidebar.tsx)
+ * renders the `data-testid="app-sidebar"` marker on `SheetContent` in its
+ * mobile branch, so this container scope — and every other
+ * `[data-testid="app-sidebar"]` rule below (hover, search box) — reaches the
+ * portaled sheet, not just the desktop `<div>` sidebar.
  */
 :root[data-buzz-sidebar] [data-testid="app-sidebar"] {
   --sidebar-active: 0 0% 100% !important;
diff --git a/desktop/src/shared/ui/sidebar.tsx b/desktop/src/shared/ui/sidebar.tsx
index 4828c15a1..25d70886b 100644
--- a/desktop/src/shared/ui/sidebar.tsx
+++ b/desktop/src/shared/ui/sidebar.tsx
@@ -319,11 +319,12 @@ const Sidebar = React.forwardRef<
 
     if (isMobile) {
       return (
-        <Sheet open={openMobile} onOpenChange={setOpenMobile} {...props}>
+        <Sheet open={openMobile} onOpenChange={setOpenMobile}>
           <SheetContent
             data-sidebar="sidebar"
             data-mobile="true"
             className="w-(--sidebar-width) bg-sidebar p-0 text-sidebar-foreground [&>button]:hidden"
+            {...props}
             style={
               {
                 "--sidebar-width": SIDEBAR_WIDTH_MOBILE,