fix(desktop): keep mac titlebar stable under zoom (#11747)

packages/app/src/components/titlebar.tsx

@@ -24,6 +24,8 @@ export function Titlebar() {
   const mac = createMemo(() => platform.platform === "desktop" && platform.os === "macos")
   const windows = createMemo(() => platform.platform === "desktop" && platform.os === "windows")
   const web = createMemo(() => platform.platform === "web")
+  const zoom = () => platform.webviewZoom?.() ?? 1
+  const minHeight = () => (mac() ? `${40 / zoom()}px` : undefined)
 
   const [history, setHistory] = createStore({
     stack: [] as string[],
@@ -134,6 +136,7 @@ export function Titlebar() {
   return (
     <header
       class="h-10 shrink-0 bg-background-base relative grid grid-cols-[auto_minmax(0,1fr)_auto] items-center"
+      style={{ "min-height": minHeight() }}
       data-tauri-drag-region
     >
       <div
@@ -145,7 +148,7 @@ export function Titlebar() {
         data-tauri-drag-region
       >
         <Show when={mac()}>
-          <div class="w-[72px] h-full shrink-0" data-tauri-drag-region />
+          <div class="h-full shrink-0" style={{ width: `${72 / zoom()}px` }} data-tauri-drag-region />
           <div class="xl:hidden w-10 shrink-0 flex items-center justify-center">
             <IconButton
               icon="menu"

packages/app/src/context/platform.tsx

@@ -1,5 +1,6 @@
 import { createSimpleContext } from "@opencode-ai/ui/context"
 import { AsyncStorage, SyncStorage } from "@solid-primitives/storage"
+import type { Accessor } from "solid-js"
 
 export type Platform = {
   /** Platform discriminator */
@@ -55,6 +56,9 @@ export type Platform = {
 
   /** Parse markdown to HTML using native parser (desktop only, returns unprocessed code blocks) */
   parseMarkdown?(markdown: string): Promise<string>
+
+  /** Webview zoom level (desktop only) */
+  webviewZoom?: Accessor<number>
 }
 
 export const { use: usePlatform, provider: PlatformProvider } = createSimpleContext({