diff --git a/desktop/src/app/components/window/window.component.html b/desktop/src/app/components/window/window.component.html
new file mode 100644
index 0000000..411c04d
--- /dev/null
+++ b/desktop/src/app/components/window/window.component.html
@@ -0,0 +1,52 @@
+<div
+  class="butterfly-window"
+  [class.active]="windowState.isActive"
+  [class.minimized]="windowState.isMinimized"
+  [class.maximized]="windowState.isMaximized"
+  [style.display]="windowState.isMinimized ? 'none' : 'flex'"
+  [style.left.px]="windowState.isMaximized ? 0 : windowState.x"
+  [style.top.px]="windowState.isMaximized ? 0 : windowState.y"
+  [style.width.px]="windowState.isMaximized ? window.innerWidth : windowState.width"
+  [style.height.px]="windowState.isMaximized ? (window.innerHeight - 48) : windowState.height"
+  [style.z-index]="windowState.zIndex"
+>
+  <!-- Title bar -->
+  <div
+    #titleBar
+    class="window-titlebar"
+    (mousedown)="onTitleBarMouseDown($event)"
+    (dblclick)="onDoubleClickTitleBar()"
+  >
+    <div class="titlebar-left">
+      <span class="window-icon">{{ windowState.icon }}</span>
+      <span class="window-title">{{ windowState.title }}</span>
+    </div>
+    <div class="titlebar-controls">
+      <button class="titlebar-btn minimize-btn" (click)="minimize.emit(windowState.id)" title="Minimize">
+        <svg width="10" height="1"><rect width="10" height="1" fill="currentColor"/></svg>
+      </button>
+      <button class="titlebar-btn maximize-btn" (click)="maximize.emit(windowState.id)" title="Maximize">
+        <svg width="10" height="10"><rect width="10" height="10" fill="none" stroke="currentColor" stroke-width="1"/></svg>
+      </button>
+      <button class="titlebar-btn close-btn" (click)="close.emit(windowState.id)" title="Close">
+        <svg width="10" height="10">
+          <line x1="0" y1="0" x2="10" y2="10" stroke="currentColor" stroke-width="1.2"/>
+          <line x1="10" y1="0" x2="0" y2="10" stroke="currentColor" stroke-width="1.2"/>
+        </svg>
+      </button>
+    </div>
+  </div>
+
+  <!-- Window body -->
+  <div class="window-body">
+    <ng-content></ng-content>
+  </div>
+
+  <!-- Resize handle -->
+  <div
+    #resizeHandle
+    class="window-resize-handle"
+    *ngIf="!windowState.isMaximized"
+    (mousedown)="onResizeMouseDown($event)"
+  ></div>
+</div>
diff --git a/desktop/src/app/components/window/window.component.scss b/desktop/src/app/components/window/window.component.scss
new file mode 100644
index 0000000..c085ff2
--- /dev/null
+++ b/desktop/src/app/components/window/window.component.scss
@@ -0,0 +1,111 @@
+:host {
+  display: contents;
+}
+
+.butterfly-window {
+  display: flex;
+  flex-direction: column;
+  position: absolute;
+  border-radius: 8px;
+  overflow: hidden;
+  box-shadow: 0 4px 24px rgba(0, 0, 0, 0.25), 0 1px 4px rgba(0, 0, 0, 0.15);
+  transition: box-shadow 0.15s ease;
+
+  &.active {
+    box-shadow: 0 8px 32px rgba(0, 0, 0, 0.35), 0 2px 8px rgba(0, 0, 0, 0.2);
+  }
+
+  &.maximized {
+    border-radius: 0;
+  }
+}
+
+// ── Title bar ─────────────────────────────────────────────────────────────
+
+.window-titlebar {
+  display: flex;
+  align-items: center;
+  justify-content: space-between;
+  height: 32px;
+  padding: 0 4px 0 12px;
+  background: linear-gradient(180deg, #3c3c3c 0%, #2d2d2d 100%);
+  color: #e0e0e0;
+  cursor: default;
+  flex-shrink: 0;
+  -webkit-app-region: drag;
+
+  .active & {
+    background: linear-gradient(180deg, #4a4a4a 0%, #3a3a3a 100%);
+  }
+}
+
+.titlebar-left {
+  display: flex;
+  align-items: center;
+  gap: 8px;
+  min-width: 0;
+  overflow: hidden;
+}
+
+.window-icon {
+  font-size: 14px;
+  flex-shrink: 0;
+}
+
+.window-title {
+  font-size: 12px;
+  font-weight: 400;
+  white-space: nowrap;
+  overflow: hidden;
+  text-overflow: ellipsis;
+  opacity: 0.95;
+}
+
+.titlebar-controls {
+  display: flex;
+  height: 100%;
+  -webkit-app-region: no-drag;
+}
+
+.titlebar-btn {
+  width: 46px;
+  height: 100%;
+  border: none;
+  background: transparent;
+  color: #e0e0e0;
+  cursor: pointer;
+  display: flex;
+  align-items: center;
+  justify-content: center;
+  transition: background-color 0.1s;
+
+  &:hover {
+    background: rgba(255, 255, 255, 0.1);
+  }
+
+  &.close-btn:hover {
+    background: #e81123;
+    color: #fff;
+  }
+}
+
+// ── Window body ───────────────────────────────────────────────────────────
+
+.window-body {
+  flex: 1;
+  background: #1e1e1e;
+  overflow: auto;
+  position: relative;
+}
+
+// ── Resize handle ─────────────────────────────────────────────────────────
+
+.window-resize-handle {
+  position: absolute;
+  bottom: 0;
+  right: 0;
+  width: 16px;
+  height: 16px;
+  cursor: nwse-resize;
+  z-index: 10;
+}
diff --git a/desktop/src/app/components/window/window.component.ts b/desktop/src/app/components/window/window.component.ts
new file mode 100644
index 0000000..5096c9e
--- /dev/null
+++ b/desktop/src/app/components/window/window.component.ts
@@ -0,0 +1,114 @@
+import {
+  Component,
+  Input,
+  Output,
+  EventEmitter,
+  ElementRef,
+  ViewChild,
+  AfterViewInit,
+  OnDestroy,
+  HostListener,
+} from '@angular/core';
+import { CommonModule } from '@angular/common';
+import { type WindowState } from '../../services/window-manager.service';
+
+@Component({
+  selector: 'app-window',
+  standalone: true,
+  imports: [CommonModule],
+  templateUrl: './window.component.html',
+  styleUrl: './window.component.scss',
+})
+export class WindowComponent implements AfterViewInit, OnDestroy {
+  @Input({ required: true }) windowState!: WindowState;
+  @Input() appContent: unknown = null; // will be projected via ng-content
+
+  @Output() close = new EventEmitter<string>();
+  @Output() minimize = new EventEmitter<string>();
+  @Output() maximize = new EventEmitter<string>();
+  @Output() focus = new EventEmitter<string>();
+  @Output() geometryChange = new EventEmitter<{ id: string; x: number; y: number; width: number; height: number }>();
+
+  @ViewChild('titleBar') titleBar!: ElementRef<HTMLDivElement>;
+  @ViewChild('resizeHandle') resizeHandle!: ElementRef<HTMLDivElement>;
+
+  private isDragging = false;
+  private isResizing = false;
+  private dragOffsetX = 0;
+  private dragOffsetY = 0;
+  private resizeStartX = 0;
+  private resizeStartY = 0;
+  private resizeStartW = 0;
+  private resizeStartH = 0;
+
+  ngAfterViewInit(): void {
+    // Click on window body to focus.
+    this.element.addEventListener('mousedown', () => this.focus.emit(this.windowState.id));
+  }
+
+  ngOnDestroy(): void {
+    document.removeEventListener('mousemove', this.onMouseMove);
+    document.removeEventListener('mouseup', this.onMouseUp);
+  }
+
+  get element(): HTMLElement {
+    return this.elementRef.nativeElement;
+  }
+
+  constructor(private elementRef: ElementRef) {}
+
+  // ── Drag ───────────────────────────────────────────────────────────────
+
+  onTitleBarMouseDown(event: MouseEvent): void {
+    if (this.windowState.isMaximized) return;
+    event.preventDefault();
+    this.isDragging = true;
+    const rect = this.element.getBoundingClientRect();
+    this.dragOffsetX = event.clientX - rect.left;
+    this.dragOffsetY = event.clientY - rect.top;
+    document.addEventListener('mousemove', this.onMouseMove);
+    document.addEventListener('mouseup', this.onMouseUp);
+    this.focus.emit(this.windowState.id);
+  }
+
+  // ── Resize ─────────────────────────────────────────────────────────────
+
+  onResizeMouseDown(event: MouseEvent): void {
+    if (this.windowState.isMaximized) return;
+    event.preventDefault();
+    event.stopPropagation();
+    this.isResizing = true;
+    this.resizeStartX = event.clientX;
+    this.resizeStartY = event.clientY;
+    this.resizeStartW = this.windowState.width;
+    this.resizeStartH = this.windowState.height;
+    document.addEventListener('mousemove', this.onMouseMove);
+    document.addEventListener('mouseup', this.onMouseUp);
+    this.focus.emit(this.windowState.id);
+  }
+
+  private onMouseMove = (event: MouseEvent): void => {
+    if (this.isDragging) {
+      const x = event.clientX - this.dragOffsetX;
+      const y = event.clientY - this.dragOffsetY;
+      this.geometryChange.emit({ id: this.windowState.id, x, y, width: this.windowState.width, height: this.windowState.height });
+    } else if (this.isResizing) {
+      const dw = event.clientX - this.resizeStartX;
+      const dh = event.clientY - this.resizeStartY;
+      const width = Math.max(this.windowState.minWidth, this.resizeStartW + dw);
+      const height = Math.max(this.windowState.minHeight, this.resizeStartH + dh);
+      this.geometryChange.emit({ id: this.windowState.id, x: this.windowState.x, y: this.windowState.y, width, height });
+    }
+  };
+
+  private onMouseUp = (): void => {
+    this.isDragging = false;
+    this.isResizing = false;
+    document.removeEventListener('mousemove', this.onMouseMove);
+    document.removeEventListener('mouseup', this.onMouseUp);
+  };
+
+  onDoubleClickTitleBar(): void {
+    this.maximize.emit(this.windowState.id);
+  }
+}