Add a toggleable Windows 7 (7.css) skin behind a new skin setting

Evaluation branch: a full Aero skin, including frameless windows with our own
title bar, switchable against the existing modern look.

The app already had a four-axis runtime skinning mechanism and zero component
stylesheets, so the skin is one new setting plus one stylesheet section rather
than a parallel UI. The key move is cascade order: 7.css is imported into a
`skin` layer ABOVE Tailwind's `utilities`, so its bare element rules outrank
the ~1900 inline utility classes already in the templates. Template changes are
limited to additive, skin-inert hooks (ARIA roles, `has-scrollbar`,
`w7-toolbar`, `w7-btn`).

- styles.css: explicit layer order, `7.css/dist/7.scoped.css` via `layer(skin)`,
  a token bridge re-pointing the existing semantic tokens at Win7 values (no new
  tokens, so `@theme inline` is untouched), a hand-authored dark Win7 palette,
  and neutralizers that `revert-layer` 7.css's dialog-button metrics back to the
  utility layer. Neutralizers must live inside `skin`, not `skinfix` —
  `revert-layer` only reaches `utilities` from one layer up.
- Frameless chrome: `chromeOptions(skin)` is now the single place either skin's
  frame is decided. `titleBarStyle: "hidden"` on every platform, which is also
  the only way to drop the macOS traffic lights. New `title-bar` component
  mounted by all three window roots.
- Window controls over RPC (minimize/toggle-maximize/close/is-maximized), served
  per window kind so the X reuses each one's existing close path — editors still
  get their dirty prompt. electrobun has no maximize event, so the state is
  derived from `resize`; double-click-to-maximize is implemented here too.
- Font: Noto Sans vendored (OFL-1.1) under ui/src/fonts, since Segoe UI is
  absent off Windows and not redistributable.

Verified: backend `tsc --noEmit` clean, `bun run build:ui` clean (486 kB initial,
under the 500 kB budget), app launches with the skin active and no console
errors. The rendered result has not been eyeballed — screen capture and
accessibility are both denied to the shell on this machine.

Co-Authored-By: Claude <noreply@anthropic.com>

ui/src/app/app.html

@@ -10,6 +10,8 @@
       </div>
     </div>
   } @else {
+    <!-- win7 skin only: the window is frameless, so this IS the chrome -->
+    <app-title-bar [title]="appName" (closeRequested)="closeWindow()" />
     <app-tab-bar />
 
     <main class="flex min-h-0 flex-1 divide-x divide-border">

ui/src/app/app.ts

@@ -17,6 +17,7 @@ import { RpcService } from './rpc.service';
 import { SettingsService } from './settings.service';
 import { StatusBar } from './status-bar/status-bar';
 import { TabBar } from './tab-bar/tab-bar';
+import { TitleBar } from './title-bar/title-bar';
 import { ToastService } from './toast.service';
 import { Toasts } from './toasts/toasts';
 import { TransferBar } from './transfer-bar/transfer-bar';
@@ -36,6 +37,7 @@ import { UpdaterService } from './updater.service';
     OverwriteDialog,
     Toasts,
     TransferBar,
+    TitleBar,
   ],
   templateUrl: './app.html',
   host: {
@@ -58,6 +60,18 @@ export class App {
   /** The connection-manager window is open — this window is modal-blocked. */
   readonly managerOpen = signal(false);
 
+  /** Shown in the win7 title bar (no native titlebar to carry it). */
+  readonly appName = BRANDING.appName;
+
+  /**
+   * win7 title bar's X. Closing the main window quits, and the app-level
+   * before-quit guard (dirty editors + running transfers) still runs — it is
+   * the one close path electrobun lets us cancel.
+   */
+  closeWindow(): void {
+    void this.rpc.request.windowClose({});
+  }
+
   constructor() {
     document.title = BRANDING.appName;
     if (this.rpc.available) {

ui/src/app/connection-manager/connection-manager.html

@@ -1,8 +1,14 @@
 <div class="flex h-screen flex-col bg-background text-foreground">
+  <!-- win7 skin only: frameless window. Fixed-size modal, so Close only. -->
+  <app-title-bar
+    [title]="i18n.t('connMgr.title')"
+    [resizable]="false"
+    (closeRequested)="close()"
+  />
   <!-- header: on macOS this row IS the titlebar (hiddenInset + drag region),
        elsewhere the native titlebar sits above and this is a compact strip -->
   <header
-    class="flex shrink-0 items-center gap-2 border-b border-border bg-chrome pr-2"
+    class="w7-toolbar flex shrink-0 items-center gap-2 border-b border-border bg-chrome pr-2"
     [class.h-10]="isMacChrome"
     [class.pl-24]="isMacChrome"
     [class.electrobun-webkit-app-region-drag]="isMacChrome"
@@ -47,7 +53,7 @@
           </button>
         </div>
 
-        <div class="flex-1 overflow-y-auto py-1">
+        <div class="has-scrollbar flex-1 overflow-y-auto py-1">
           <!-- stacks -->
           @for (group of store.grouped().stacks; track group.stack.id) {
             <div
@@ -175,7 +181,7 @@
       <!-- edit form -->
       <div class="flex min-w-0 flex-1 flex-col">
         @if (draft(); as d) {
-          <div class="grid flex-1 auto-rows-min grid-cols-2 gap-x-4 gap-y-3 overflow-y-auto p-5">
+          <div class="has-scrollbar grid flex-1 auto-rows-min grid-cols-2 gap-x-4 gap-y-3 overflow-y-auto p-5">
             <label class="col-span-2 flex flex-col gap-1 text-xs">
               <span class="text-muted-foreground">{{ i18n.t('connMgr.name') }}</span>
               <input

ui/src/app/connection-manager/connection-manager.ts

@@ -9,6 +9,7 @@ import { DialogsService } from '../dialogs.service';
 import { blockNativeContextMenu, IS_MAC_CHROME } from '../platform';
 import { RpcService } from '../rpc.service';
 import { SettingsService } from '../settings.service';
+import { TitleBar } from '../title-bar/title-bar';
 import { Toasts } from '../toasts/toasts';
 
 interface Draft {
@@ -72,7 +73,7 @@ function fromDraft(d: Draft): SavedConnection {
  */
 @Component({
   selector: 'app-root',
-  imports: [NgIcon, ConfirmDialog, PromptDialog, Toasts],
+  imports: [NgIcon, ConfirmDialog, PromptDialog, Toasts, TitleBar],
   templateUrl: './connection-manager.html',
   host: {
     '(window:keydown.escape)': 'onEscape()',

ui/src/app/dialogs/chmod-dialog.ts

@@ -60,13 +60,13 @@ const PERMS = ['r', 'w', 'x'] as const;
         <div class="mt-4 flex justify-end gap-2">
           <button
             (click)="cancel()"
-            class="rounded-md px-3 py-1.5 text-xs font-medium hover:bg-accent"
+            class="w7-btn rounded-md px-3 py-1.5 text-xs font-medium hover:bg-accent"
           >
             {{ i18n.t('common.cancel') }}
           </button>
           <button
             (click)="submit()"
-            class="rounded-md bg-primary px-3 py-1.5 text-xs font-medium text-primary-foreground hover:bg-primary/90"
+            class="w7-btn rounded-md bg-primary px-3 py-1.5 text-xs font-medium text-primary-foreground hover:bg-primary/90"
           >
             {{ i18n.t('common.apply') }}
           </button>

ui/src/app/dialogs/confirm-dialog.ts

@@ -17,7 +17,7 @@ import { FocusService } from '../focus.service';
         <div class="mt-4 flex justify-end gap-2">
           <button
             (click)="cancel()"
-            class="rounded-md px-3 py-1.5 text-xs font-medium hover:bg-accent"
+            class="w7-btn rounded-md px-3 py-1.5 text-xs font-medium hover:bg-accent"
           >
             {{ i18n.t('common.cancel') }}
           </button>
@@ -26,8 +26,8 @@ import { FocusService } from '../focus.service';
             (click)="submit()"
             [class]="
               request().destructive
-                ? 'rounded-md bg-destructive px-3 py-1.5 text-xs font-medium text-destructive-foreground hover:bg-destructive/90'
-                : 'rounded-md bg-primary px-3 py-1.5 text-xs font-medium text-primary-foreground hover:bg-primary/90'
+                ? 'w7-btn rounded-md bg-destructive px-3 py-1.5 text-xs font-medium text-destructive-foreground hover:bg-destructive/90'
+                : 'w7-btn rounded-md bg-primary px-3 py-1.5 text-xs font-medium text-primary-foreground hover:bg-primary/90'
             "
           >
             {{ request().confirmLabel }}

ui/src/app/dialogs/overwrite-dialog.ts

@@ -79,7 +79,7 @@ import { FocusService } from '../focus.service';
         <div class="mt-4 flex items-center gap-2">
           <button
             (click)="pick('cancel')"
-            class="rounded-md px-3 py-1.5 text-xs font-medium text-muted-foreground hover:bg-accent hover:text-foreground"
+            class="w7-btn rounded-md px-3 py-1.5 text-xs font-medium text-muted-foreground hover:bg-accent hover:text-foreground"
           >
             {{ i18n.t('common.cancel') }}
           </button>
@@ -101,14 +101,14 @@ import { FocusService } from '../focus.service';
           }
           <button
             (click)="pick('skip')"
-            class="rounded-md px-3 py-1.5 text-xs font-medium hover:bg-accent"
+            class="w7-btn rounded-md px-3 py-1.5 text-xs font-medium hover:bg-accent"
           >
             {{ i18n.t('dialogs.skip') }}
           </button>
           <button
             #primaryBtn
             (click)="pick('overwrite')"
-            class="rounded-md bg-primary px-3 py-1.5 text-xs font-medium text-primary-foreground hover:bg-primary/90"
+            class="w7-btn rounded-md bg-primary px-3 py-1.5 text-xs font-medium text-primary-foreground hover:bg-primary/90"
           >
             {{ isDir() ? i18n.t('dialogs.merge') : i18n.t('dialogs.replace') }}
           </button>

ui/src/app/dialogs/prompt-dialog.ts

@@ -33,14 +33,14 @@ import { FocusService } from '../focus.service';
         <div class="mt-4 flex justify-end gap-2">
           <button
             (click)="cancel()"
-            class="rounded-md px-3 py-1.5 text-xs font-medium hover:bg-accent"
+            class="w7-btn rounded-md px-3 py-1.5 text-xs font-medium hover:bg-accent"
           >
             {{ i18n.t('common.cancel') }}
           </button>
           <button
             (click)="submit()"
             [disabled]="!value().trim()"
-            class="rounded-md bg-primary px-3 py-1.5 text-xs font-medium text-primary-foreground hover:bg-primary/90 disabled:opacity-50"
+            class="w7-btn rounded-md bg-primary px-3 py-1.5 text-xs font-medium text-primary-foreground hover:bg-primary/90 disabled:opacity-50"
           >
             {{ request().confirmLabel }}
           </button>

ui/src/app/editor-window/editor-window.html

@@ -10,10 +10,13 @@
       </div>
     </div>
   } @else {
+    <!-- win7 skin only: the window is frameless. The X runs the SAME dirty
+         prompt as ⌘W and the Close button — never a raw window close. -->
+    <app-title-bar [title]="ctx.name + (dirty() ? ' *' : '')" (closeRequested)="requestClose()" />
     <!-- header: on macOS this row IS the titlebar (hiddenInset + drag region),
          elsewhere the native titlebar sits above and this is a compact strip -->
     <header
-      class="flex shrink-0 items-center gap-2 border-b border-border bg-chrome pr-2"
+      class="w7-toolbar flex shrink-0 items-center gap-2 border-b border-border bg-chrome pr-2"
       [class.h-10]="isMacChrome"
       [class.pl-24]="isMacChrome"
       [class.electrobun-webkit-app-region-drag]="isMacChrome"

ui/src/app/editor-window/editor-window.ts

@@ -15,6 +15,7 @@ import { ALT_LABEL, blockNativeContextMenu, EDITOR_CONTEXT, IS_MAC_CHROME, MOD_L
 import { RpcService } from '../rpc.service';
 import { SettingsService } from '../settings.service';
 import { ToastService } from '../toast.service';
+import { TitleBar } from '../title-bar/title-bar';
 import { Toasts } from '../toasts/toasts';
 
 /** Debounce for mirroring the draft to bun (the traffic-light-close safety net). */
@@ -30,7 +31,7 @@ const DRAFT_DEBOUNCE_MS = 400;
  */
 @Component({
   selector: 'app-root',
-  imports: [NgIcon, Toasts],
+  imports: [NgIcon, Toasts, TitleBar],
   templateUrl: './editor-window.html',
   host: {
     '(window:keydown)': 'onKeydown($event)',

ui/src/app/file-panel/file-panel.html

@@ -84,7 +84,7 @@
   @if (menuOpen()) {
     <div class="fixed inset-0 z-20" (click)="menuOpen.set(false)"></div>
     <div
-      class="absolute top-full left-2 z-30 mt-1 max-h-80 w-64 overflow-y-auto rounded-lg border border-border bg-card py-1 text-card-foreground shadow-xl"
+      class="has-scrollbar absolute top-full left-2 z-30 mt-1 max-h-80 w-64 overflow-y-auto rounded-lg border border-border bg-card py-1 text-card-foreground shadow-xl"
     >
       <button
         (click)="pickLocal()"
@@ -238,7 +238,7 @@
   (keydown)="onKeydown($event)"
   (mousedown)="activate()"
   (contextmenu)="listContextMenu($event)"
-  class="h-full overflow-y-auto outline-none"
+  class="has-scrollbar h-full overflow-y-auto outline-none"
 >
   @if (panel().connecting()) {
     <div class="panel-fade-in grid h-full place-items-center">

ui/src/app/platform.ts

@@ -8,6 +8,9 @@ declare global {
     __APP_PLATFORM?: string;
     /** Which root component this window boots. */
     __APP_MODE?: 'main' | 'editor' | 'manager';
+    /** Persisted skin — decides the window's native chrome, so it has to be
+     *  known before first paint (see chromeOptions in src/bun/windows.ts). */
+    __APP_SKIN?: 'modern' | 'win7';
     /** Window-kind specific context (EditorOpenContext for editor windows). */
     __APP_CTX?: unknown;
   }
@@ -15,14 +18,32 @@ declare global {
 
 export const PLATFORM = typeof window !== 'undefined' ? (window.__APP_PLATFORM ?? '') : '';
 
-/** True when the window uses macOS hiddenInset chrome (header fused with titlebar). */
-export const IS_MAC_CHROME = PLATFORM === 'darwin';
+const IS_MAC = PLATFORM === 'darwin';
+
+/**
+ * The win7 skin makes the window frameless on EVERY platform and draws its own
+ * Aero title bar, so this is a window-chrome fact, not just a settings value —
+ * it is baked into the preload rather than read from SettingsService, which
+ * resolves too late for layout. Toggling the setting only affects windows
+ * opened afterwards.
+ */
+export const IS_WIN7_CHROME =
+  typeof window !== 'undefined' && window.__APP_SKIN === 'win7';
+
+/**
+ * True when macOS traffic lights overlay the app's header row (the fused
+ * hiddenInset layout, which reserves pl-24 for them). False under the win7
+ * skin even on macOS: titleBarStyle 'hidden' removes the traffic lights, so
+ * reserving space for them would leave a gap.
+ */
+export const IS_MAC_CHROME = IS_MAC && !IS_WIN7_CHROME;
 
 export const IS_WINDOWS = PLATFORM === 'win32';
 
-/** Shortcut-hint labels: "⌘W" on macOS, "Ctrl+W" elsewhere. */
-export const MOD_LABEL = IS_MAC_CHROME ? '⌘' : 'Ctrl+';
-export const ALT_LABEL = IS_MAC_CHROME ? '⌥' : 'Alt+';
+/** Shortcut-hint labels: "⌘W" on macOS, "Ctrl+W" elsewhere. Keyed on the real
+ *  platform, NOT IS_MAC_CHROME — the keyboard does not change with the skin. */
+export const MOD_LABEL = IS_MAC ? '⌘' : 'Ctrl+';
+export const ALT_LABEL = IS_MAC ? '⌥' : 'Alt+';
 
 export const APP_MODE: 'main' | 'editor' | 'manager' =
   typeof window !== 'undefined' ? (window.__APP_MODE ?? 'main') : 'main';

ui/src/app/rpc.service.ts

@@ -32,6 +32,7 @@ export class RpcService {
   private managerStateListeners = new Set<(open: boolean) => void>();
   private connectionsListeners = new Set<() => void>();
   private updateStatusListeners = new Set<(status: UpdateStatus) => void>();
+  private windowStateListeners = new Set<(maximized: boolean) => void>();
 
   private rpc: ReturnType<typeof Electroview.defineRPC<AppRPC>> | undefined;
   private ready: Promise<void> = Promise.resolve();
@@ -71,6 +72,9 @@ export class RpcService {
           updateStatus: (status) => {
             for (const listener of this.updateStatusListeners) listener(status);
           },
+          windowState: ({ maximized }) => {
+            for (const listener of this.windowStateListeners) listener(maximized);
+          },
         },
       },
     });
@@ -123,6 +127,12 @@ export class RpcService {
     this.updateStatusListeners.add(listener);
   }
 
+  /** win7 skin: the frameless window's maximize state changed (derived from
+   *  the native resize event, so Aero Snap and Win+Up land here too). */
+  onWindowState(listener: (maximized: boolean) => void): void {
+    this.windowStateListeners.add(listener);
+  }
+
   /** Typed request proxy: `await rpc.request.listDir({...})`. Waits for the bridge. */
   get request() {
     const rpc = this.rpc;

ui/src/app/settings.service.ts

@@ -7,6 +7,7 @@ import { RpcService } from './rpc.service';
 @Injectable({ providedIn: 'root' })
 export class SettingsService {
   readonly locale = signal<AppSettings['locale']>(DEFAULT_SETTINGS.locale);
+  readonly skin = signal<AppSettings['skin']>(DEFAULT_SETTINGS.skin);
   readonly theme = signal<AppSettings['theme']>(DEFAULT_SETTINGS.theme);
   readonly darkTone = signal<AppSettings['darkTone']>(DEFAULT_SETTINGS.darkTone);
   readonly accent = signal<AppSettings['accent']>(DEFAULT_SETTINGS.accent);
@@ -40,6 +41,7 @@ export class SettingsService {
       .addEventListener('change', (e) => this.systemDark.set(e.matches));
     // the default accent is not the CSS default — apply before first paint
     this.applyAccent();
+    this.applySkin();
     if (!this.rpc.available) return;
     void this.rpc.request.getSettings({}).then((res) => {
       if (res.ok) this.applyAll(res.settings);
@@ -50,6 +52,7 @@ export class SettingsService {
 
   private applyAll(settings: AppSettings): void {
     this.locale.set(settings.locale);
+    this.skin.set(settings.skin);
     this.theme.set(settings.theme);
     this.darkTone.set(settings.darkTone);
     this.accent.set(settings.accent);
@@ -62,6 +65,7 @@ export class SettingsService {
     this.autoClearCompleted.set(settings.autoClearCompleted);
     this.editor.set(settings.editor);
     this.editorApp.set(settings.editorApp);
+    this.applySkin();
     this.applyTheme();
     this.applyDarkTone();
     this.applyAccent();
@@ -75,6 +79,12 @@ export class SettingsService {
     void this.persist();
   }
 
+  setSkin(skin: AppSettings['skin']): void {
+    this.skin.set(skin);
+    this.applySkin();
+    void this.persist();
+  }
+
   setTheme(theme: AppSettings['theme']): void {
     this.theme.set(theme);
     this.applyTheme();
@@ -142,6 +152,16 @@ export class SettingsService {
     void this.persist();
   }
 
+  /**
+   * The odd one out: a CLASS, not a data-* attribute. 7.scoped.css is
+   * precompiled to require a literal `.win7` ancestor, so the class is not
+   * ours to choose. Default ("modern") = class absent, matching the
+   * delete-when-default rule the other axes follow.
+   */
+  private applySkin(): void {
+    document.documentElement.classList.toggle('win7', this.skin() === 'win7');
+  }
+
   private applyTheme(): void {
     const theme = this.theme();
     if (theme === 'system') {
@@ -185,6 +205,7 @@ export class SettingsService {
   protected settings(): AppSettings {
     return {
       locale: this.locale(),
+      skin: this.skin(),
       theme: this.theme(),
       darkTone: this.darkTone(),
       accent: this.accent(),

ui/src/app/tab-bar/tab-bar.ts

@@ -5,11 +5,12 @@ import { LOCALE_LABELS, SUPPORTED } from '@shared/i18n';
 import type { AccentTone } from '@shared/types';
 import { I18nService } from '../i18n.service';
 import { PanelsService } from '../panels.service';
-import { IS_MAC_CHROME, MOD_LABEL } from '../platform';
+import { IS_MAC_CHROME, IS_WIN7_CHROME, MOD_LABEL } from '../platform';
 import { RpcService } from '../rpc.service';
 import { SettingsService } from '../settings.service';
 import { UpdaterService } from '../updater.service';
 
+const SKINS = ['modern', 'win7'] as const;
 const THEMES = ['system', 'light', 'dark'] as const;
 const DARK_TONES = ['dark', 'darker'] as const;
 // Swatch colors are fixed mid-tones so every dot reads on both light and dark
@@ -41,7 +42,7 @@ const CONCURRENCY_CHOICES = [2, 3, 4, 6, 8] as const;
     <!-- On macOS this row IS the titlebar (hiddenInset): taller, padded past the
          traffic lights, and draggable. Elsewhere it's a normal compact row. -->
     <div
-      class="relative flex items-center gap-0.5 border-b border-border bg-chrome pr-1.5 electrobun-webkit-app-region-drag"
+      class="w7-toolbar relative flex items-center gap-0.5 border-b border-border bg-chrome pr-1.5 electrobun-webkit-app-region-drag"
       [class.h-10]="isMacChrome"
       [class.pl-24]="isMacChrome"
       [class.pl-1.5]="!isMacChrome"
@@ -180,6 +181,30 @@ const CONCURRENCY_CHOICES = [2, 3, 4, 6, 8] as const;
             </select>
           </div>
 
+          <div class="mt-2.5 flex items-center justify-between gap-2">
+            <span class="text-xs text-muted-foreground">{{ i18n.t('options.skin.label') }}</span>
+            <div class="flex rounded-md border border-border p-0.5">
+              @for (option of skins; track option) {
+                <button
+                  (click)="settings.setSkin(option)"
+                  class="rounded px-2 py-0.5 text-[11px]"
+                  [class.bg-accent]="settings.skin() === option"
+                  [class.text-foreground]="settings.skin() === option"
+                  [class.text-muted-foreground]="settings.skin() !== option"
+                >
+                  {{ i18n.t('options.skin.' + option) }}
+                </button>
+              }
+            </div>
+          </div>
+          <!-- The CSS half of the skin flips live; the window frame does not
+               (titleBarStyle is fixed at construction — see chromeOptions). -->
+          @if (settings.skin() !== bootSkin) {
+            <p class="mt-1 text-right text-[10px] text-muted-foreground">
+              {{ i18n.t('options.skin.restartHint') }}
+            </p>
+          }
+
           <div class="mt-2.5 flex items-center justify-between gap-2">
             <span class="text-xs text-muted-foreground">{{ i18n.t('options.theme.label') }}</span>
             <div class="flex rounded-md border border-border p-0.5">
@@ -436,6 +461,10 @@ export class TabBar {
   readonly modLabel = MOD_LABEL;
   readonly appName = BRANDING.appName;
   readonly buildLabel = BRANDING.buildLabel;
+  readonly skins = SKINS;
+  /** What the window was BUILT with, not the current setting — the frameless
+   *  chrome only changes on reopen, so the hint compares against this. */
+  readonly bootSkin: (typeof SKINS)[number] = IS_WIN7_CHROME ? 'win7' : 'modern';
   readonly themes = THEMES;
   readonly darkTones = DARK_TONES;
   readonly accents = ACCENTS;

ui/src/app/title-bar/title-bar.ts

@@ -0,0 +1,72 @@
+import { Component, inject, input, output, signal } from '@angular/core';
+import { IS_WIN7_CHROME } from '../platform';
+import { RpcService } from '../rpc.service';
+
+/**
+ * The win7 skin's Aero title bar. Rendered by all three window kinds, and only
+ * when `IS_WIN7_CHROME` — under that skin the native frame is gone
+ * (titleBarStyle 'hidden'), so this row IS the window's chrome.
+ *
+ * The markup is 7.css's contract, not ours: `.title-bar` > `.title-bar-text` +
+ * `.title-bar-controls` > buttons keyed by `aria-label` (Minimize / Maximize /
+ * Restore / Close each get their own glyph). Nothing here is styled with
+ * Tailwind on purpose — the whole row comes from @layer skin.
+ *
+ * Dragging rides on electrobun's preload drag-region classes. Two things
+ * electrobun does NOT provide and this component implements:
+ *   - double-click to maximize (it only wires mousedown/mouseup)
+ *   - the maximize/restore glyph state, which has no event; bun derives it
+ *     from the native resize and pushes `windowState` (see trackMaximizeState).
+ */
+@Component({
+  selector: 'app-title-bar',
+  template: `
+    @if (enabled) {
+      <div class="title-bar electrobun-webkit-app-region-drag" (dblclick)="toggle()">
+        <div class="title-bar-text">{{ title() }}</div>
+        <div class="title-bar-controls electrobun-webkit-app-region-no-drag">
+          @if (resizable()) {
+            <button aria-label="Minimize" (click)="minimize()"></button>
+            <button
+              [attr.aria-label]="maximized() ? 'Restore' : 'Maximize'"
+              (click)="toggle()"
+            ></button>
+          }
+          <button aria-label="Close" (click)="closeRequested.emit()"></button>
+        </div>
+      </div>
+    }
+  `,
+})
+export class TitleBar {
+  readonly title = input('');
+  /** The manager window is a fixed-size modal — it gets Close only. */
+  readonly resizable = input(true);
+  /** Hosts decide what closing means (quit / dirty prompt / managerClose). */
+  readonly closeRequested = output<void>();
+
+  protected readonly enabled = IS_WIN7_CHROME;
+  protected readonly maximized = signal(false);
+
+  private readonly rpc = inject(RpcService);
+
+  constructor() {
+    if (!this.enabled || !this.rpc.available) return;
+    // No maximize event exists, so seed from a one-shot read and then follow
+    // the resize-derived push (which also covers Aero Snap and Win+Up).
+    void this.rpc.request.windowIsMaximized({}).then((res) => {
+      if (res.ok) this.maximized.set(res.maximized);
+    });
+    this.rpc.onWindowState((maximized) => this.maximized.set(maximized));
+  }
+
+  protected minimize(): void {
+    void this.rpc.request.windowMinimize({});
+  }
+
+  protected toggle(): void {
+    void this.rpc.request.windowToggleMaximize({}).then((res) => {
+      if (res.ok) this.maximized.set(res.maximized);
+    });
+  }
+}

ui/src/app/transfer-bar/transfer-bar.html

@@ -11,7 +11,7 @@
       <ng-icon name="mynaTrash" size="0.75rem" /> {{ i18n.t('transfer.clearFinished') }}
     </button>
   </div>
-  <div class="max-h-40 overflow-y-auto border-t border-border bg-chrome">
+  <div class="has-scrollbar max-h-40 overflow-y-auto border-t border-border bg-chrome">
     @for (job of transfers.jobs(); track job.id) {
       <div class="flex items-center gap-2 px-3 py-1.5 text-xs">
         <ng-icon [name]="stateIcon(job)" size="0.95rem" [class]="stateClass(job)" />
@@ -19,7 +19,16 @@
         <div class="min-w-0 flex-1">
           <div class="truncate text-[11px] text-muted-foreground">{{ progressLabel(job) }}</div>
           @if (isActive(job)) {
-            <div class="mt-0.5 h-1 overflow-hidden rounded-full bg-muted">
+            <!-- role+aria are 7.css's hook for the Win7 progress bar
+                 ([role=progressbar] > div); under the modern skin they are
+                 inert and the Tailwind classes below still draw the bar. -->
+            <div
+              role="progressbar"
+              aria-valuemin="0"
+              aria-valuemax="100"
+              [attr.aria-valuenow]="jobPercent(job)"
+              class="mt-0.5 h-1 overflow-hidden rounded-full bg-muted"
+            >
               <div
                 class="h-full rounded-full bg-primary transition-[width] duration-100"
                 [style.width.%]="jobPercent(job)"

ui/src/index.html

@@ -20,6 +20,17 @@
         html:not([data-theme='light']) { background: oklch(0.2178 0.002 107); }
         html:not([data-theme='light'])[data-dark-tone='darker'] { background: oklch(0 0 0); }
       }
+      /* win7 skin: same four states, mirroring the .win7 --background values
+         in styles.css. The preload adds this class before any page script, so
+         it is already on <html> here. Omitting this arm makes every win7
+         window flash white before styles.css parses. */
+      html.win7 { background: #ffffff; }
+      html.win7[data-theme='dark'] { background: #1f1f1f; }
+      html.win7[data-theme='dark'][data-dark-tone='darker'] { background: #121212; }
+      @media (prefers-color-scheme: dark) {
+        html.win7:not([data-theme='light']) { background: #1f1f1f; }
+        html.win7:not([data-theme='light'])[data-dark-tone='darker'] { background: #121212; }
+      }
     </style>
   </head>
   <body>

ui/src/styles.css

@@ -1,4 +1,23 @@
+/* Layer order — declared BEFORE the imports so it wins (a @layer statement is
+   one of the only two rule types allowed above @import). `skin` sorts after
+   `utilities`, so every 7.css rule outranks every Tailwind utility on the
+   elements it targets; that inversion is what lets the win7 skin restyle
+   ~1900 inline utility classes without touching the templates. `skinfix` is
+   above both, and uses `revert-layer` to hand individual properties back to
+   `utilities` where 7.css's Win7-dialog metrics are wrong for this app.
+   Tailwind re-declares the first four names, a no-op once ordered here.
+   See the "Windows 7 skin" section at the bottom of this file. */
+@layer theme, base, components, utilities, skin, skinfix;
 @import "tailwindcss";
+/* The SCOPED 7.css build: postcss-prefix-selector rewrote every selector to
+   `.win7` (root rules) or `.win7 <sel>` (the rest), so the whole framework is
+   inert until SettingsService.applySkin puts that class on <html>. All 61
+   icons are data URIs, so nothing needs copying into assets — and NOT the
+   `7.inline.css` build, which flattens away the --w7-* vars the dark palette
+   below depends on. The deep path is required: 7.css ships no `exports` map
+   and Tailwind's resolver only reads `style`/`mainFields`, so a bare
+   `@import "7.css"` finds no entry. */
+@import "7.css/dist/7.scoped.css" layer(skin);
 
 /* shadcn-style theme tokens. Light stays the zinc family; the dark neutrals are a
    warm gray family (hue ~107) anchored on #1a1a19 — see the dark blocks below.
@@ -276,3 +295,300 @@ body {
   user-select: none;
   cursor: default;
 }
+
+/* ==========================================================================
+   Windows 7 skin — SettingsService.applySkin puts `.win7` on <html>
+   ==========================================================================
+
+   Three tiers, and the split matters:
+
+   - `@layer skin` (the 7.css import at the top of this file) owns the
+     CONTROLS: buttons, inputs, tabs, progress bars, tree views, the Aero
+     title bar. It sits ABOVE `utilities`, so a bare `button` rule in 7.css
+     beats `.rounded-md` on that same button. That inversion is the whole
+     trick — it restyles ~1900 inline utility classes with no template edits.
+   - This unlayered section owns the BRIDGE: it re-points the app's own
+     semantic tokens at Win7 values, so utilities Tailwind still controls
+     (bg-card, border-border, text-muted-foreground) also come out
+     Win7-correct. It adds NO new tokens on purpose — a new colour token
+     would need a matching `--color-*` line in `@theme inline`.
+   - `@layer skinfix` (last, above `skin`) hands individual properties BACK to
+     the utilities layer with `revert-layer`, for the places where 7.css's
+     Win7-dialog metrics are wrong for this app.
+
+   WARNING for future edits: because `skin` outranks `utilities`, any Tailwind
+   utility added later to a <button>, <input>, <select>, <textarea> or <table>
+   silently loses under this skin. `skinfix` is the only place to fix that.
+
+   Specificity notes — the blocks below must beat the token blocks above:
+     :root.win7                    (0,2,0) beats base :root          (0,1,0)
+     :root.win7[data-theme='dark'] (0,3,0) beats :root[data-theme=…] (0,2,0)
+                                   and ties the darker-tone block    (0,3,0),
+                                   winning on source order (it is last).
+   The accent formula blocks are deliberately NOT overridden: they only set
+   --primary/--ring/--cursor-tint, and letting them through is what makes the
+   accent picker recolour the Aero chrome — authentic, Win7 shipped exactly
+   that ("Window Color" personalization). */
+
+/* Segoe UI is not on macOS/Linux and is not redistributable. Noto Sans is the
+   substitute 7.css itself names in its --w7-font fallback stack. Vendored
+   (OFL-1.1) from @fontsource/noto-sans@5.3.0, files/noto-sans-latin-{400,700}
+   -normal.woff2 -> ui/src/fonts/. Vendored rather than @imported from
+   node_modules because Tailwind inlines imported CSS, which would leave
+   @fontsource's relative url() rebased against the wrong directory. They live
+   under src/ (not public/) so esbuild emits them as hashed assets and rewrites
+   the url() — a public/ path is not resolvable at build time. */
+@font-face {
+  font-family: 'Noto Sans App';
+  font-style: normal;
+  font-weight: 400;
+  font-display: block;
+  src: url('./fonts/noto-sans-latin-400-normal.woff2') format('woff2');
+}
+@font-face {
+  font-family: 'Noto Sans App';
+  font-style: normal;
+  font-weight: 700;
+  font-display: block;
+  src: url('./fonts/noto-sans-latin-700-normal.woff2') format('woff2');
+}
+
+:root.win7 {
+  /* Real Segoe first (Windows), bundled substitute everywhere else. */
+  --w7-family: 'Segoe UI', 'SegoeUI', 'Noto Sans App', system-ui, sans-serif;
+  /* ~7.css's 9pt, but in px so it tracks the interface-size axis below.
+     Restating the `font` SHORTHAND (not just the family) is deliberate:
+     7.css applies `font: var(--w7-font)` on 12 component rules, and the
+     shorthand also resets weight and line-height — pinning 400/1.4 here stops
+     those rules from flattening the app's `font-medium` / leading. */
+  --w7-fs: 12px;
+  --w7-font: 400 var(--w7-fs) / 1.4 var(--w7-family);
+
+  /* Surface ramp, Win7 Explorer. This INVERTS the modern ramp's direction:
+     there --chrome (frame strips) sits below --background (content panes);
+     here the content pane is the brightest thing on screen and the frame is
+     the #f0f0f0 window surface. Deliberate — that is what Explorer was. */
+  --background: #ffffff;
+  --chrome: #f0f0f0;
+  --card: #f0f0f0;
+  --foreground: #000000;
+  --card-foreground: #000000;
+  --muted-foreground: #6d6d6d;
+  --secondary: #e8e8e8;
+  --secondary-foreground: #000000;
+  --muted: #e8e8e8;
+  /* Win7's hover is a pale blue wash, not a grey — matches --w7-el-grad-h */
+  --accent: #eaf6fd;
+  --accent-foreground: #000000;
+  --border: #d5d5d5;
+  --input: #abadb3; /* 7.css's own text-input border */
+  --destructive: #c62828;
+  --destructive-foreground: #ffffff;
+  --success: #06b025; /* the Win7 progress-bar green */
+
+  /* 5px, NOT 3px: `rounded-md` is 74 of the 112 radius utilities in the
+     templates and compiles to calc(var(--radius) - 2px), so 5 lands it exactly
+     on --w7-el-bdr (3px). --radius itself feeds `rounded-lg` (12 uses) at 5px,
+     near the 6px window radius. Bare `rounded` (26 uses) is a Tailwind literal
+     0.25rem and is unaffected. */
+  --radius: 5px;
+}
+
+/* Interface size: Win7 shipped this exact axis ("Smaller / Medium / Larger"),
+   so scaling is more authentic than disabling it. One indirection covers all
+   three tiers because var substitution is lazy. The --row-h / --list-font
+   block further up scales the file list independently and is untouched. */
+:root.win7[data-text='compact'] { --w7-fs: 11px; }
+:root.win7[data-text='large'] { --w7-fs: 13px; }
+
+/* Hand-authored dark Win7. Microsoft never shipped one — this exists so the
+   theme and tone settings stay live under the skin. Only the colour-carrying
+   --w7-* vars are listed: --w7-el-grad and --w7-w-grad are DERIVED from the
+   values below and recolour for free, while --w7-el-grad-h/-a and
+   --w7-li-bg-hl are literal hex in 7.css and so must be restated. The ~25
+   geometry vars and ~20 base64 icon vars are theme-independent.
+   DUPLICATED for forced-dark and system-dark, per the rule the token blocks
+   above set: every dark value goes in BOTH. */
+:root.win7[data-theme='dark'] {
+  --w7-surface: #2b2b2b;
+  --w7-el-bg: #3a3a3a;
+  --w7-el-bg-d: #333333;
+  --w7-el-bg-s-1: #333333;
+  --w7-el-bg-s-2: #262626;
+  --w7-el-bd: #565656;
+  --w7-el-bd-h: #4a8cbe;
+  --w7-el-bd-a: #3f6c8c;
+  --w7-el-bd-d: #3f3f3f;
+  --w7-el-c: #f0f0f0;
+  --w7-el-c-d: #6f6f6f;
+  --w7-el-sd: inset 0 0 0 1px #ffffff14;
+  --w7-el-grad-h: linear-gradient(#3c5a6b 45%, #315062 45%, #2b4557);
+  --w7-el-grad-a: linear-gradient(#2c4657, #24384a 30% 50%, #1d2f3f 50%, #16242f);
+  --w7-li-bd-hl: #3f6c8c;
+  --w7-li-bg-hl: linear-gradient(#ffffff14, #4a6b8433 90%, #ffffff1a);
+  --w7-w-bd: #000000d9;
+  --w7-w-bg: #1f3a52;
+  --w7-tab-bg: #2b2b2b;
+  --w7-title-c: #8ab4e8;
+  --w7-link-c: #6fb3ff;
+  --w7-link-c-h: #9acbff;
+
+  --background: #1f1f1f;
+  --chrome: #2b2b2b;
+  --card: #2b2b2b;
+  --foreground: #f0f0f0;
+  --card-foreground: #f0f0f0;
+  --muted-foreground: #a0a0a0;
+  --secondary: #383838;
+  --secondary-foreground: #f0f0f0;
+  --muted: #383838;
+  --accent: #2f4a5c;
+  --accent-foreground: #f0f0f0;
+  --border: #3c3c3c;
+  --input: #55585c;
+}
+@media (prefers-color-scheme: dark) {
+  :root.win7:not([data-theme='light']) {
+    --w7-surface: #2b2b2b;
+    --w7-el-bg: #3a3a3a;
+    --w7-el-bg-d: #333333;
+    --w7-el-bg-s-1: #333333;
+    --w7-el-bg-s-2: #262626;
+    --w7-el-bd: #565656;
+    --w7-el-bd-h: #4a8cbe;
+    --w7-el-bd-a: #3f6c8c;
+    --w7-el-bd-d: #3f3f3f;
+    --w7-el-c: #f0f0f0;
+    --w7-el-c-d: #6f6f6f;
+    --w7-el-sd: inset 0 0 0 1px #ffffff14;
+    --w7-el-grad-h: linear-gradient(#3c5a6b 45%, #315062 45%, #2b4557);
+    --w7-el-grad-a: linear-gradient(#2c4657, #24384a 30% 50%, #1d2f3f 50%, #16242f);
+    --w7-li-bd-hl: #3f6c8c;
+    --w7-li-bg-hl: linear-gradient(#ffffff14, #4a6b8433 90%, #ffffff1a);
+    --w7-w-bd: #000000d9;
+    --w7-w-bg: #1f3a52;
+    --w7-tab-bg: #2b2b2b;
+    --w7-title-c: #8ab4e8;
+    --w7-link-c: #6fb3ff;
+    --w7-link-c-h: #9acbff;
+
+    --background: #1f1f1f;
+    --chrome: #2b2b2b;
+    --card: #2b2b2b;
+    --foreground: #f0f0f0;
+    --card-foreground: #f0f0f0;
+    --muted-foreground: #a0a0a0;
+    --secondary: #383838;
+    --secondary-foreground: #f0f0f0;
+    --muted: #383838;
+    --accent: #2f4a5c;
+    --accent-foreground: #f0f0f0;
+    --border: #3c3c3c;
+    --input: #55585c;
+  }
+}
+
+/* Dark tone "darker": Aero has no meaningful true black, so rather than leave
+   the Tone row a dead control the skin just goes a step deeper. Duplicated
+   forced + system like everything else. */
+:root.win7[data-theme='dark'][data-dark-tone='darker'] {
+  --w7-surface: #1a1a1a;
+  --w7-el-bg: #262626;
+  --w7-w-bg: #12202c;
+  --background: #121212;
+  --chrome: #1a1a1a;
+  --card: #1a1a1a;
+}
+@media (prefers-color-scheme: dark) {
+  :root.win7:not([data-theme='light'])[data-dark-tone='darker'] {
+    --w7-surface: #1a1a1a;
+    --w7-el-bg: #262626;
+    --w7-w-bg: #12202c;
+    --background: #121212;
+    --chrome: #1a1a1a;
+    --card: #1a1a1a;
+  }
+}
+
+/* Accent -> Aero window colour, so the existing accent picker keeps meaning
+   under the skin. --w7-w-bg is the one colour 7.css documents as settable. */
+:root.win7[data-accent] {
+  --w7-w-bg: var(--primary);
+}
+
+/* Unlayered on purpose: the html/body rule above sets font-family unlayered,
+   so a layered override would lose. Family only — NOT font-size: the app's
+   rem-based utilities are root-relative, and shifting the root would move
+   every line box for no gain. */
+.win7 body {
+  font-family: var(--w7-family);
+}
+
+/* Neutralizers live in `skin`, NOT `skinfix`, and this is load-bearing:
+   `revert-layer` rolls a property back to the previous LAYER, so from inside
+   `skin` it lands on `utilities` (the Tailwind classes already in the
+   templates) — which is the whole point. From `skinfix` it would land back on
+   7.css and do nothing. Within `skin` these beat the imported rules on equal
+   specificity by source order, since the import is at the top of this file. */
+@layer skin {
+  /* 7.css sizes every <button> like a Win7 dialog push button
+     (min-width 75px, min-height 23px, padding 0 12px). Most of this app's 84
+     buttons are ~24px icon squares sized by utilities, so without this the tab
+     bar wraps and the options popover overflows. Hand the BOX MODEL back to
+     the utilities layer and keep 7.css's paint. The title bar's own controls
+     are matched by a MORE specific 7.css selector (.title-bar-controls button)
+     and so keep their Aero glyph metrics untouched. */
+  .win7 button {
+    min-width: 0;
+    min-height: 0;
+    padding: revert-layer;
+    text-align: revert-layer;
+    color: revert-layer;
+  }
+
+  /* 7.css hardcodes #fff / #abadb3 / #222 on form controls and tables, outside
+     its own var system. Reverting routes them back through the bridged tokens
+     above, which is what makes dark mode nearly free. */
+  .win7 input[type='text'],
+  .win7 input[type='password'],
+  .win7 input[type='number'],
+  .win7 input[type='search'],
+  .win7 textarea {
+    background-color: revert-layer;
+    border-color: revert-layer;
+  }
+  .win7 table {
+    background-color: revert-layer;
+    color: revert-layer;
+  }
+
+  /* Win7 toolbar buttons are FLAT with a hover glow, not Aero slabs —
+     Explorer's command bar worked exactly that way. `w7-toolbar` marks the
+     three header rows; a plain `.title-bar` sibling is deliberately NOT one of
+     them, so its controls keep the real Aero treatment. `w7-flat` is the
+     per-button escape hatch. Both classes are inert under the modern skin. */
+  .win7 .w7-toolbar button,
+  .win7 .w7-flat {
+    background: revert-layer;
+    border-color: transparent;
+    box-shadow: none;
+  }
+  .win7 .w7-toolbar button::before,
+  .win7 .w7-toolbar button::after,
+  .win7 .w7-flat::before,
+  .win7 .w7-flat::after {
+    content: none;
+  }
+}
+
+/* Above `skin`, for rules that must state a value rather than defer to a
+   neighbouring layer. */
+@layer skinfix {
+  /* Opt back IN to real Win7 push-button metrics, for the dialog and options
+     buttons where they are right. Inert under the modern skin. */
+  .win7 .w7-btn {
+    min-width: 75px;
+    min-height: 23px;
+    padding: 0 12px;
+  }
+}