fix: remove maximize border artifact on Windows frameless window

Remove the body padding compensation hack that was causing a visible
white border when maximized. Electron 28 handles WM_NCCALCSIZE
internally, making the manual offset unnecessary.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Author: Caldis

src/main/index.ts

@@ -7,7 +7,7 @@
 import os from 'os';
 import path from 'path';
 import type { OpenDialogOptions, SaveDialogOptions } from 'electron';
-import { app, BrowserWindow, ipcMain, dialog, shell, screen } from 'electron';
+import { app, BrowserWindow, ipcMain, dialog, shell } from 'electron';
 import { autoUpdater } from 'electron-updater';
 import MenuBuilder from './menu';
 import mainI18n from './i18n';
@@ -111,6 +111,7 @@ if (!gotLock) {
       hasShadow: true,
       // 窗口背景透明 (在非启用AERO的Win机器上会有窗口冻结的BUG
       transparent: false,
+      backgroundColor: '#18191b',
       // 无边框窗口
       frame: platform === 'darwin',
       // OSX下, 窗口按钮内置
@@ -160,17 +161,10 @@ if (!gotLock) {
 
     // Forward maximize/unmaximize events to renderer (for title bar button sync)
     mainWindow.on('maximize', () => {
-      // Detect the invisible border size (window extends beyond screen when maximized)
-      let border = 0;
-      if (mainWindow) {
-        const bounds = mainWindow.getBounds();
-        const display = screen.getDisplayMatching(bounds);
-        border = Math.max(0, display.workArea.x - bounds.x);
-      }
-      mainWindow?.webContents.send('window-maximized-change', true, border);
+      mainWindow?.webContents.send('window-maximized-change', true);
     });
     mainWindow.on('unmaximize', () => {
-      mainWindow?.webContents.send('window-maximized-change', false, 0);
+      mainWindow?.webContents.send('window-maximized-change', false);
     });
 
     // ── Close guard ────────────────────────────────────────────

src/renderer/components/TitleBar/button/index.tsx

@@ -6,32 +6,26 @@ import useAppStore from '../../../store';
 // Electron API (via preload contextBridge)
 const { electronAPI } = window;
 
-/** Apply or remove maximized-state styles on body/root */
-function applyMaximizedStyles(isMaximized: boolean, border: number) {
-  const body = document.querySelector('body')!;
+/** Apply or remove maximized-state styles on root */
+function applyMaximizedStyles(isMaximized: boolean) {
   const root = document.querySelector<HTMLElement>('#root')!;
   if (isMaximized) {
-    // Add padding to compensate for window extending beyond screen edges
-    body.style.padding = border > 0 ? `${border}px` : '0';
     root.style.borderRadius = '0';
   } else {
-    body.style.removeProperty('padding');
     root.style.removeProperty('border-radius');
   }
 }
 
 function TitleBarButtonGroup() {
   const [maximized, setMaximized] = useState(() => electronAPI.windowIsMaximized());
-  const [border, setBorder] = useState(0);
   const [pinned, setPinned] = useState(false);
   const sideEditorVisible = useAppStore((state: any) => state.sideEditorVisible);
 
   // Listen to ALL maximize/unmaximize events (button click, double-click title bar, Win+Up, etc.)
   useEffect(() => {
-    return electronAPI.onMaximizedChange((isMaximized, borderSize) => {
+    return electronAPI.onMaximizedChange((isMaximized) => {
       setMaximized(isMaximized);
-      setBorder(borderSize);
-      applyMaximizedStyles(isMaximized, borderSize);
+      applyMaximizedStyles(isMaximized);
     });
   }, []);
 
@@ -68,8 +62,7 @@ function TitleBarButtonGroup() {
   } as const;
 
   // Center buttons in the 58px safe area: (58-30)/2 = 14px from content edge
-  // When maximized, add border offset to compensate for window oversize
-  const offset = { top: border + 14, right: border + 14 };
+  const offset = { top: 14, right: 14 };
 
   return (
     <div

src/renderer/index.global.css

@@ -10,7 +10,7 @@ html, body {
 }
 
 body {
-    background-color: rgba(0,0,0,0);
+    background-color: hsl(var(--surface));
     overflow: hidden;
 }
 #root {