diff --git a/packages/frontend/src/App.vue b/packages/frontend/src/App.vue
index 4f3ecb0..fc8b2dd 100644
--- a/packages/frontend/src/App.vue
+++ b/packages/frontend/src/App.vue
@@ -21,7 +21,8 @@ const viewKey = computed(() => {
     route.name === 'drawio-editor' ||
     route.name === 'cad-viewer' ||
     route.name === 'model3d-viewer' ||
-    route.name === 'tools-scanner'
+    route.name === 'tools-scanner' ||
+    route.name === 'tools-bg-remove'
   ) {
     return String(route.name);
   }
@@ -41,6 +42,7 @@ const viewKey = computed(() => {
         'CadViewerView',
         'Model3DViewerView',
         'ToolsScannerView',
+        'ToolsBgRemoveView',
       ]"
       :max="10"
     >
diff --git a/packages/frontend/src/composables/useFileDropZone.ts b/packages/frontend/src/composables/useFileDropZone.ts
new file mode 100644
index 0000000..15993e7
--- /dev/null
+++ b/packages/frontend/src/composables/useFileDropZone.ts
@@ -0,0 +1,41 @@
+import { ref } from 'vue';
+
+/** Nested dragenter/leave safe file drop handlers for a page root. */
+export function useFileDropZone(onFiles: (files: File[]) => void) {
+  const dropActive = ref(false);
+  let depth = 0;
+
+  function onDragEnter(event: DragEvent) {
+    event.preventDefault();
+    depth += 1;
+    dropActive.value = true;
+    if (event.dataTransfer) event.dataTransfer.dropEffect = 'copy';
+  }
+
+  function onDragOver(event: DragEvent) {
+    event.preventDefault();
+    if (event.dataTransfer) event.dataTransfer.dropEffect = 'copy';
+  }
+
+  function onDragLeave(event: DragEvent) {
+    event.preventDefault();
+    depth = Math.max(0, depth - 1);
+    if (depth === 0) dropActive.value = false;
+  }
+
+  function onDrop(event: DragEvent) {
+    event.preventDefault();
+    depth = 0;
+    dropActive.value = false;
+    const files = Array.from(event.dataTransfer?.files ?? []);
+    if (files.length) onFiles(files);
+  }
+
+  return {
+    dropActive,
+    onDragEnter,
+    onDragOver,
+    onDragLeave,
+    onDrop,
+  };
+}
diff --git a/packages/frontend/src/config/favicons.ts b/packages/frontend/src/config/favicons.ts
index aa182e2..9f50b67 100644
--- a/packages/frontend/src/config/favicons.ts
+++ b/packages/frontend/src/config/favicons.ts
@@ -18,6 +18,7 @@ export type FaviconKind =
   | 'cad'
   | 'model3d'
   | 'scanner'
+  | 'bgremove'
   | 'text'
   | 'csv'
   | 'file';
@@ -37,6 +38,8 @@ export const ICON_PATHS: Record<FaviconKind, string> = {
   cad: 'M3 3H21V21H3V3M5 5V19H19V5H5M7 17V15H9V13H11V11H13V9H15V7H17V17H7Z',
   model3d: 'M12 2L21 7V17L12 22L3 17V7L12 2M12 4.3L5.4 8L12 11.7L18.6 8L12 4.3M5 9.7V15.8L11 19.1V13.1L5 9.7M13 19.1L19 15.8V9.7L13 13.1V19.1Z',
   scanner: 'M4 4H10V6H6V10H4V4M14 4H20V10H18V6H14V4M4 14H6V18H10V20H4V14M18 14H20V20H14V18H18V14M8 8H16V16H8V8Z',
+  bgremove:
+    'M19.36,2.72L20.78,4.14L15.06,9.85C16.13,11.39 16.28,13.24 15.38,14.44L9.06,8.12C10.26,7.22 12.11,7.37 13.65,8.44L19.36,2.72M5.93,17.57C3.92,15.56 2.69,13.16 2.35,10.92L7.23,8.83L14.67,16.27L12.58,21.15C10.34,20.81 7.94,19.58 5.93,17.57Z',
   text: 'M6,2A2,2 0 0,0 4,4V20A2,2 0 0,0 6,22H18A2,2 0 0,0 20,20V8L14,2H6M6,4H13V9H18V20H6V4M8,12V14H16V12H8M8,16V18H13V16H8Z',
   csv: 'M14 2H6C4.9 2 4 2.9 4 4V20C4 21.1 4.9 22 6 22H18C19.1 22 20 21.1 20 20V8L14 2M18 20H6V4H13V9H18V20M10 19L12 15H9V10H15V15L13 19H10',
   file: 'M6,2A2,2 0 0,0 4,4V20A2,2 0 0,0 6,22H18A2,2 0 0,0 20,20V8L14,2H6M6,4H13V9H18V20H6V4M8,12V14H16V12H8M8,16V18H13V16H8Z',
@@ -55,6 +58,7 @@ export const ICON_COLORS: Record<FaviconKind, string> = {
   cad: '#5c6bc0',
   model3d: '#6d4c41',
   scanner: '#00897b',
+  bgremove: '#5c6bc0',
   text: '#607d8b',
   csv: '#00838f',
   file: '#546e7a',
@@ -114,6 +118,7 @@ const EXT_KIND: Record<string, FaviconKind> = {
   webp: 'scanner',
   gif: 'scanner',
   bmp: 'scanner',
+  bgremove: 'bgremove',
   txt: 'text',
 };
 
diff --git a/packages/frontend/src/integrations/bgremove/removeBg.ts b/packages/frontend/src/integrations/bgremove/removeBg.ts
new file mode 100644
index 0000000..c2653fa
--- /dev/null
+++ b/packages/frontend/src/integrations/bgremove/removeBg.ts
@@ -0,0 +1,254 @@
+export type BgRemoveMode = 'threshold' | 'flood';
+
+export interface BgRemoveOptions {
+  /** 0–100: how far from sampled background still counts as background */
+  tolerance: number;
+  /** 0–100: soft edge width beyond hard threshold */
+  feather: number;
+  mode: BgRemoveMode;
+}
+
+export interface Rgb {
+  r: number;
+  g: number;
+  b: number;
+}
+
+export const DEFAULT_BG_REMOVE_OPTIONS: BgRemoveOptions = {
+  tolerance: 28,
+  feather: 12,
+  mode: 'threshold',
+};
+
+function clampByte(value: number) {
+  return Math.min(255, Math.max(0, Math.round(value)));
+}
+
+function colorDistance(a: Rgb, r: number, g: number, b: number) {
+  return Math.max(Math.abs(r - a.r), Math.abs(g - a.g), Math.abs(b - a.b));
+}
+
+function median(values: number[]) {
+  if (!values.length) return 0;
+  const sorted = [...values].sort((a, b) => a - b);
+  const mid = Math.floor(sorted.length / 2);
+  return sorted.length % 2
+    ? sorted[mid]!
+    : Math.round((sorted[mid - 1]! + sorted[mid]!) / 2);
+}
+
+/** Sample corner neighborhoods and take per-channel median as background. */
+export function sampleCornerBackground(
+  data: Uint8ClampedArray,
+  width: number,
+  height: number,
+  radius = 2,
+): Rgb {
+  const rs: number[] = [];
+  const gs: number[] = [];
+  const bs: number[] = [];
+  const corners: Array<[number, number]> = [
+    [0, 0],
+    [width - 1, 0],
+    [0, height - 1],
+    [width - 1, height - 1],
+  ];
+
+  for (const [cx, cy] of corners) {
+    for (let dy = -radius; dy <= radius; dy += 1) {
+      for (let dx = -radius; dx <= radius; dx += 1) {
+        const x = Math.min(width - 1, Math.max(0, cx + dx));
+        const y = Math.min(height - 1, Math.max(0, cy + dy));
+        const i = (y * width + x) * 4;
+        rs.push(data[i]!);
+        gs.push(data[i + 1]!);
+        bs.push(data[i + 2]!);
+      }
+    }
+  }
+
+  return { r: median(rs), g: median(gs), b: median(bs) };
+}
+
+function hardLimit(tolerance: number) {
+  return Math.round((Math.min(100, Math.max(0, tolerance)) / 100) * 180);
+}
+
+function featherWidth(feather: number) {
+  return Math.round((Math.min(100, Math.max(0, feather)) / 100) * 80);
+}
+
+function alphaForDistance(
+  distance: number,
+  hard: number,
+  soft: number,
+  originalAlpha: number,
+) {
+  if (distance <= hard) return 0;
+  if (soft <= 0 || distance >= hard + soft) return originalAlpha;
+  const t = (distance - hard) / soft;
+  return clampByte(originalAlpha * t);
+}
+
+function loadImage(source: string | Blob | HTMLImageElement | HTMLCanvasElement) {
+  if (source instanceof HTMLCanvasElement) {
+    return Promise.resolve(source);
+  }
+  if (source instanceof HTMLImageElement) {
+    if (source.complete && source.naturalWidth) return Promise.resolve(source);
+    return new Promise<HTMLImageElement>((resolve, reject) => {
+      source.onload = () => resolve(source);
+      source.onerror = () =>
+        reject(new Error('이미지를 불러오지 못했습니다.'));
+    });
+  }
+
+  const objectUrl =
+    typeof source === 'string' ? null : URL.createObjectURL(source);
+  const src = typeof source === 'string' ? source : objectUrl!;
+  return new Promise<HTMLImageElement>((resolve, reject) => {
+    const image = new Image();
+    image.onload = () => {
+      if (objectUrl) URL.revokeObjectURL(objectUrl);
+      resolve(image);
+    };
+    image.onerror = () => {
+      if (objectUrl) URL.revokeObjectURL(objectUrl);
+      reject(new Error('이미지를 불러오지 못했습니다.'));
+    };
+    image.src = src;
+  });
+}
+
+function drawToCanvas(
+  image: HTMLImageElement | HTMLCanvasElement,
+): HTMLCanvasElement {
+  if (image instanceof HTMLCanvasElement) {
+    const copy = document.createElement('canvas');
+    copy.width = image.width;
+    copy.height = image.height;
+    const ctx = copy.getContext('2d', { willReadFrequently: true });
+    if (!ctx) throw new Error('Canvas를 초기화하지 못했습니다.');
+    ctx.drawImage(image, 0, 0);
+    return copy;
+  }
+  const canvas = document.createElement('canvas');
+  canvas.width = image.naturalWidth || image.width;
+  canvas.height = image.naturalHeight || image.height;
+  const ctx = canvas.getContext('2d', { willReadFrequently: true });
+  if (!ctx) throw new Error('Canvas를 초기화하지 못했습니다.');
+  ctx.drawImage(image, 0, 0);
+  return canvas;
+}
+
+function applyThreshold(
+  data: Uint8ClampedArray,
+  bg: Rgb,
+  hard: number,
+  soft: number,
+) {
+  for (let i = 0; i < data.length; i += 4) {
+    const d = colorDistance(bg, data[i]!, data[i + 1]!, data[i + 2]!);
+    data[i + 3] = alphaForDistance(d, hard, soft, data[i + 3]!);
+  }
+}
+
+function applyFlood(
+  data: Uint8ClampedArray,
+  width: number,
+  height: number,
+  bg: Rgb,
+  hard: number,
+  soft: number,
+) {
+  const total = width * height;
+  const match = new Uint8Array(total);
+  const limit = hard + soft;
+  for (let p = 0; p < total; p += 1) {
+    const i = p * 4;
+    const d = colorDistance(bg, data[i]!, data[i + 1]!, data[i + 2]!);
+    if (d <= limit) match[p] = 1;
+  }
+
+  const visited = new Uint8Array(total);
+  const queue = new Int32Array(total);
+  let head = 0;
+  let tail = 0;
+
+  const seed = (x: number, y: number) => {
+    const p = y * width + x;
+    if (!match[p] || visited[p]) return;
+    visited[p] = 1;
+    queue[tail++] = p;
+  };
+
+  seed(0, 0);
+  seed(width - 1, 0);
+  seed(0, height - 1);
+  seed(width - 1, height - 1);
+
+  while (head < tail) {
+    const p = queue[head++]!;
+    const x = p % width;
+    const y = (p / width) | 0;
+    if (x > 0) seed(x - 1, y);
+    if (x + 1 < width) seed(x + 1, y);
+    if (y > 0) seed(x, y - 1);
+    if (y + 1 < height) seed(x, y + 1);
+  }
+
+  for (let p = 0; p < total; p += 1) {
+    if (!visited[p]) continue;
+    const i = p * 4;
+    const d = colorDistance(bg, data[i]!, data[i + 1]!, data[i + 2]!);
+    data[i + 3] = alphaForDistance(d, hard, soft, data[i + 3]!);
+  }
+}
+
+export async function removeBackgroundBySample(
+  source: string | Blob | HTMLImageElement | HTMLCanvasElement,
+  options: Partial<BgRemoveOptions> = {},
+): Promise<{
+  blob: Blob;
+  url: string;
+  width: number;
+  height: number;
+  background: Rgb;
+}> {
+  const opts = { ...DEFAULT_BG_REMOVE_OPTIONS, ...options };
+  const image = await loadImage(source);
+  const canvas = drawToCanvas(image);
+  const ctx = canvas.getContext('2d', { willReadFrequently: true });
+  if (!ctx) throw new Error('Canvas를 초기화하지 못했습니다.');
+
+  const imageData = ctx.getImageData(0, 0, canvas.width, canvas.height);
+  const { data, width, height } = imageData;
+  const background = sampleCornerBackground(data, width, height);
+  const hard = hardLimit(opts.tolerance);
+  const soft = featherWidth(opts.feather);
+
+  if (opts.mode === 'flood') {
+    applyFlood(data, width, height, background, hard, soft);
+  } else {
+    applyThreshold(data, background, hard, soft);
+  }
+
+  ctx.putImageData(imageData, 0, 0);
+  const blob = await new Promise<Blob>((resolve, reject) => {
+    canvas.toBlob(
+      (value) =>
+        value
+          ? resolve(value)
+          : reject(new Error('투명 PNG를 만들지 못했습니다.')),
+      'image/png',
+    );
+  });
+
+  return {
+    blob,
+    url: URL.createObjectURL(blob),
+    width: canvas.width,
+    height: canvas.height,
+    background,
+  };
+}
diff --git a/packages/frontend/src/router/index.ts b/packages/frontend/src/router/index.ts
index 9eb2a67..82ada3d 100644
--- a/packages/frontend/src/router/index.ts
+++ b/packages/frontend/src/router/index.ts
@@ -49,6 +49,11 @@ const router = createRouter({
       name: 'tools-scanner',
       component: () => import('@/views/ToolsScannerView.vue'),
     },
+    {
+      path: '/tools/bg-remove',
+      name: 'tools-bg-remove',
+      component: () => import('@/views/ToolsBgRemoveView.vue'),
+    },
     {
       path: '/licenses',
       name: 'licenses',
diff --git a/packages/frontend/src/views/CadViewerView.vue b/packages/frontend/src/views/CadViewerView.vue
index 3c28ee4..1181866 100644
--- a/packages/frontend/src/views/CadViewerView.vue
+++ b/packages/frontend/src/views/CadViewerView.vue
@@ -14,6 +14,7 @@ import {
 } from '@mlightcad/cad-simple-viewer';
 import AppShell from '@/components/AppShell.vue';
 import EditorToolbar from '@/components/EditorToolbar.vue';
+import { useFileDropZone } from '@/composables/useFileDropZone';
 import { consumeViewerFiles } from '@/composables/viewerSession';
 import { usePageTitle } from '@/composables/usePageTitle';
 import { useSystemTheme } from '@/composables/useSystemTheme';
@@ -52,7 +53,12 @@ settings.set('isShowToolbar', true);
 
 function applyFiles(files: File[]) {
   const file = files.find((item) => /\.(?:dxf|dwg)$/i.test(item.name));
-  if (!file) return;
+  if (!file) {
+    if (files.length) {
+      error.value = '.dxf 또는 .dwg 파일을 선택해 주세요.';
+    }
+    return;
+  }
   pendingFile.value = file;
   if (fontReady.value) localFile.value = file;
   filename.value = file.name;
@@ -63,6 +69,14 @@ function applyFiles(files: File[]) {
       : '';
 }
 
+const {
+  dropActive,
+  onDragEnter,
+  onDragOver,
+  onDragLeave,
+  onDrop,
+} = useFileDropZone(applyFiles);
+
 async function initialize() {
   applyFiles(consumeViewerFiles('cad'));
   try {
@@ -98,10 +112,6 @@ function onFileSelected(event: Event) {
   const files = Array.from(input.files ?? []);
   input.value = '';
   if (!files.length) return;
-  if (!files.some((file) => /\.(?:dxf|dwg)$/i.test(file.name))) {
-    error.value = '.dxf 또는 .dwg 파일을 선택해 주세요.';
-    return;
-  }
   applyFiles(files);
   void nextTick();
 }
@@ -126,7 +136,14 @@ function onClose() {
 
 <template>
   <AppShell :editor="true">
-    <div class="cad-page">
+    <div
+      class="cad-page"
+      :class="{ 'is-drop-active': dropActive }"
+      @dragenter="onDragEnter"
+      @dragover="onDragOver"
+      @dragleave="onDragLeave"
+      @drop="onDrop"
+    >
       <EditorToolbar
         :filename="filename"
         :show-save="false"
@@ -160,9 +177,15 @@ function onClose() {
         />
         <div v-if="ready && !localFile && viewerCreated" class="empty-state">
           <strong>CAD 도면을 선택해 주세요.</strong>
-          <span>DXF와 DWG 파일은 브라우저 안에서만 처리됩니다.</span>
+          <span>
+            DXF와 DWG 파일을 열거나 이 영역으로 끌어다 놓으세요. 처리는
+            브라우저 안에서만 이뤄집니다.
+          </span>
           <button type="button" @click="onOpen">파일 열기</button>
         </div>
+        <div v-if="dropActive" class="drop-overlay" aria-hidden="true">
+          DXF · DWG 파일을 놓으세요
+        </div>
       </div>
     </div>
   </AppShell>
@@ -231,6 +254,20 @@ function onClose() {
   cursor: pointer;
 }
 
+.drop-overlay {
+  position: absolute;
+  inset: 0.75rem;
+  z-index: 30;
+  display: grid;
+  place-items: center;
+  border: 2px dashed var(--accent);
+  border-radius: 8px;
+  background: color-mix(in srgb, var(--accent-soft) 88%, transparent);
+  color: var(--ink);
+  font-weight: 650;
+  pointer-events: none;
+}
+
 .sr-only {
   position: absolute;
   width: 1px;
diff --git a/packages/frontend/src/views/HomeView.vue b/packages/frontend/src/views/HomeView.vue
index 68f7c8f..09fc93f 100644
--- a/packages/frontend/src/views/HomeView.vue
+++ b/packages/frontend/src/views/HomeView.vue
@@ -69,6 +69,12 @@ const toolTypes = [
     title: '문서 스캐너',
     subtitle: '코너 보정 · OCR · PDF',
   },
+  {
+    route: 'tools-bg-remove',
+    extension: 'bgremove',
+    title: '배경 제거',
+    subtitle: '로고 단색 배경 · 투명 PNG',
+  },
 ] as const;
 
 function onDrop(e: DragEvent) {
diff --git a/packages/frontend/src/views/Model3DViewerView.vue b/packages/frontend/src/views/Model3DViewerView.vue
index 8d766e9..1bb60f6 100644
--- a/packages/frontend/src/views/Model3DViewerView.vue
+++ b/packages/frontend/src/views/Model3DViewerView.vue
@@ -13,6 +13,7 @@ import Model3DCanvas from '@/components/model3d/Model3DCanvas.vue';
 import ModelTreeItem from '@/components/model3d/ModelTreeItem.vue';
 import { MODEL3D_EXTENSIONS } from '@/config/app';
 import { consumeViewerFiles } from '@/composables/viewerSession';
+import { useFileDropZone } from '@/composables/useFileDropZone';
 import { usePageTitle } from '@/composables/usePageTitle';
 import { useSystemTheme } from '@/composables/useSystemTheme';
 import {
@@ -135,6 +136,14 @@ function onFilesSelected(event: Event) {
   if (selected.length) applyFiles(selected);
 }
 
+const {
+  dropActive,
+  onDragEnter,
+  onDragOver,
+  onDragLeave,
+  onDrop,
+} = useFileDropZone(applyFiles);
+
 function onProgress(value: number, label: string) {
   progress.value = value;
   progressLabel.value = label;
@@ -238,7 +247,14 @@ function onClose() {
 
 <template>
   <AppShell :editor="true">
-    <div class="model-page">
+    <div
+      class="model-page"
+      :class="{ 'is-drop-active': dropActive }"
+      @dragenter="onDragEnter"
+      @dragover="onDragOver"
+      @dragleave="onDragLeave"
+      @drop="onDrop"
+    >
       <EditorToolbar
         :filename="filename"
         save-label="내보내기"
@@ -314,8 +330,8 @@ function onClose() {
           <div v-else class="empty-state">
             <strong>3D 모델을 선택해 주세요.</strong>
             <span>
-              Online3DViewer가 지원하는 형식과 ZIP, 보조 텍스처를 함께 열 수
-              있습니다.
+              Online3DViewer가 지원하는 형식과 ZIP, 보조 텍스처를 함께 열거나
+              이 영역으로 끌어다 놓을 수 있습니다.
             </span>
             <button type="button" @click="onOpen">파일 열기</button>
           </div>
@@ -369,6 +385,10 @@ function onClose() {
             <progress :value="progressPercent" max="100" />
             <small>{{ progressPercent }}%</small>
           </div>
+
+          <div v-if="dropActive" class="drop-overlay" aria-hidden="true">
+            3D 모델 파일을 놓으세요
+          </div>
         </main>
 
         <aside class="inspector">
@@ -632,6 +652,20 @@ function onClose() {
   text-align: right;
 }
 
+.drop-overlay {
+  position: absolute;
+  inset: 0.75rem;
+  z-index: 25;
+  display: grid;
+  place-items: center;
+  border: 2px dashed var(--accent);
+  border-radius: 8px;
+  background: color-mix(in srgb, var(--accent-soft) 88%, transparent);
+  color: var(--ink);
+  font-weight: 650;
+  pointer-events: none;
+}
+
 .export-bar {
   display: flex;
   flex-wrap: wrap;
diff --git a/packages/frontend/src/views/ToolsBgRemoveView.vue b/packages/frontend/src/views/ToolsBgRemoveView.vue
new file mode 100644
index 0000000..2de7130
--- /dev/null
+++ b/packages/frontend/src/views/ToolsBgRemoveView.vue
@@ -0,0 +1,642 @@
+<script setup lang="ts">
+import { computed, onBeforeUnmount, ref, watch } from 'vue';
+import { useRouter } from 'vue-router';
+import AppShell from '@/components/AppShell.vue';
+import EditorToolbar from '@/components/EditorToolbar.vue';
+import { useFileDropZone } from '@/composables/useFileDropZone';
+import { usePageTitle } from '@/composables/usePageTitle';
+import {
+  DEFAULT_BG_REMOVE_OPTIONS,
+  removeBackgroundBySample,
+  type BgRemoveMode,
+  type Rgb,
+} from '@/integrations/bgremove/removeBg';
+import { downloadBlob } from '@/utils/downloadBlob';
+
+defineOptions({ name: 'ToolsBgRemoveView' });
+
+const router = useRouter();
+const fileInput = ref<HTMLInputElement | null>(null);
+const filename = ref('배경 제거');
+const sourceUrl = ref<string | null>(null);
+const resultUrl = ref<string | null>(null);
+const background = ref<Rgb | null>(null);
+const busy = ref(false);
+const error = ref('');
+const notice = ref('');
+const tolerance = ref(DEFAULT_BG_REMOVE_OPTIONS.tolerance);
+const feather = ref(DEFAULT_BG_REMOVE_OPTIONS.feather);
+const mode = ref<BgRemoveMode>(DEFAULT_BG_REMOVE_OPTIONS.mode);
+const imageUrlInput = ref('');
+
+usePageTitle(filename);
+
+const hasImage = computed(() => Boolean(sourceUrl.value));
+const bgCss = computed(() => {
+  if (!background.value) return '';
+  const { r, g, b } = background.value;
+  return `rgb(${r}, ${g}, ${b})`;
+});
+
+function revoke(url: string | null) {
+  if (url?.startsWith('blob:')) URL.revokeObjectURL(url);
+}
+
+function baseName(name = filename.value) {
+  return name.replace(/\.[^.]+$/, '') || 'logo';
+}
+
+function onClose() {
+  void router.push({ name: 'home' });
+}
+
+function onOpen() {
+  fileInput.value?.click();
+}
+
+function isImageFile(file: File) {
+  if (file.type.startsWith('image/')) return true;
+  return /\.(png|jpe?g|webp|gif|bmp|svg)$/i.test(file.name);
+}
+
+async function loadFile(file: File) {
+  if (!isImageFile(file)) {
+    error.value = 'PNG, JPEG, WebP, GIF, BMP, SVG 이미지를 선택해 주세요.';
+    return;
+  }
+  error.value = '';
+  notice.value = '';
+  revoke(sourceUrl.value);
+  revoke(resultUrl.value);
+  sourceUrl.value = URL.createObjectURL(file);
+  resultUrl.value = null;
+  background.value = null;
+  filename.value = file.name;
+  await processImage();
+}
+
+async function loadFromUrl(raw = imageUrlInput.value) {
+  const trimmed = raw.trim();
+  if (!trimmed) {
+    error.value = '이미지 URL을 입력해 주세요.';
+    return;
+  }
+  let parsed: URL;
+  try {
+    parsed = new URL(trimmed);
+  } catch {
+    error.value = '올바른 이미지 URL을 입력해 주세요.';
+    return;
+  }
+  if (parsed.protocol !== 'http:' && parsed.protocol !== 'https:') {
+    error.value = 'http(s) URL만 사용할 수 있습니다.';
+    return;
+  }
+
+  busy.value = true;
+  error.value = '';
+  notice.value = '';
+  try {
+    const response = await fetch(parsed.href, { mode: 'cors' });
+    if (!response.ok) {
+      throw new Error(`이미지를 가져오지 못했습니다 (${response.status}).`);
+    }
+    const blob = await response.blob();
+    const looksImage =
+      blob.type.startsWith('image/') ||
+      /\.(png|jpe?g|webp|gif|bmp|svg)(\?|$)/i.test(parsed.pathname);
+    if (!looksImage) {
+      throw new Error('응답이 이미지가 아닙니다.');
+    }
+    const leaf = decodeURIComponent(
+      parsed.pathname.split('/').filter(Boolean).pop() || 'image',
+    );
+    const name = /\.[a-z0-9]+$/i.test(leaf) ? leaf : `${leaf}.png`;
+    const file = new File([blob], name, {
+      type: blob.type || 'image/png',
+    });
+    imageUrlInput.value = parsed.href;
+    await loadFile(file);
+  } catch (reason) {
+    const message =
+      reason instanceof Error ? reason.message : 'URL에서 이미지를 불러오지 못했습니다.';
+    error.value = /Failed to fetch|NetworkError|CORS/i.test(message)
+      ? '이미지를 가져오지 못했습니다. CORS를 허용하는 URL인지 확인해 주세요.'
+      : message;
+  } finally {
+    busy.value = false;
+  }
+}
+
+function onFilesSelected(event: Event) {
+  const input = event.target as HTMLInputElement;
+  const file = input.files?.[0];
+  input.value = '';
+  if (file) void loadFile(file);
+}
+
+const {
+  dropActive,
+  onDragEnter,
+  onDragOver,
+  onDragLeave,
+  onDrop: onZoneDrop,
+} = useFileDropZone((files) => {
+  const file = files[0];
+  if (file) void loadFile(file);
+});
+
+async function processImage() {
+  if (!sourceUrl.value) return;
+  busy.value = true;
+  error.value = '';
+  try {
+    const result = await removeBackgroundBySample(sourceUrl.value, {
+      tolerance: tolerance.value,
+      feather: feather.value,
+      mode: mode.value,
+    });
+    revoke(resultUrl.value);
+    resultUrl.value = result.url;
+    background.value = result.background;
+    notice.value = '배경을 제거했습니다.';
+  } catch (reason) {
+    error.value =
+      reason instanceof Error ? reason.message : '배경 제거에 실패했습니다.';
+  } finally {
+    busy.value = false;
+  }
+}
+
+function exportPng() {
+  if (!resultUrl.value) return;
+  void fetch(resultUrl.value)
+    .then((response) => response.blob())
+    .then((blob) => downloadBlob(blob, `${baseName()}-transparent.png`));
+}
+
+watch(mode, () => {
+  if (sourceUrl.value) void processImage();
+});
+
+onBeforeUnmount(() => {
+  revoke(sourceUrl.value);
+  revoke(resultUrl.value);
+});
+</script>
+
+<template>
+  <AppShell :editor="true">
+    <div
+      class="bg-page"
+      :class="{ 'is-drop-active': dropActive }"
+      @dragenter="onDragEnter"
+      @dragover="onDragOver"
+      @dragleave="onDragLeave"
+      @drop="onZoneDrop"
+    >
+      <EditorToolbar
+        :filename="filename"
+        save-label="PNG 저장"
+        :show-save="Boolean(resultUrl)"
+        :busy="busy"
+        @open="onOpen"
+        @save="exportPng"
+        @close="onClose"
+      />
+      <input
+        ref="fileInput"
+        class="sr-only"
+        type="file"
+        accept="image/png,image/jpeg,image/webp,image/gif,image/bmp,image/svg+xml,.png,.jpg,.jpeg,.webp,.gif,.bmp,.svg"
+        @change="onFilesSelected"
+      />
+
+      <p v-if="error" class="viewer-message viewer-message--error" role="alert">
+        {{ error }}
+      </p>
+      <p v-else-if="notice" class="viewer-message">{{ notice }}</p>
+
+      <main class="workspace">
+        <div
+          v-if="!hasImage"
+          class="empty"
+          :class="{ 'is-drop-active': dropActive }"
+        >
+          <strong>배경 제거</strong>
+          <p>
+            단색 배경 로고 이미지를 열거나 끌어다 놓으면 모서리 색을 기준으로
+            배경을 투명하게 만듭니다. 흰 배경·검은 배경 모두 처리됩니다.
+          </p>
+          <button
+            type="button"
+            class="btn-primary"
+            :disabled="busy"
+            @click="onOpen"
+          >
+            이미지 열기
+          </button>
+          <form class="url-form" @submit.prevent="void loadFromUrl()">
+            <input
+              v-model="imageUrlInput"
+              type="url"
+              inputmode="url"
+              placeholder="https://example.com/logo.png"
+              :disabled="busy"
+              aria-label="이미지 URL"
+            />
+            <button type="submit" :disabled="busy">URL 불러오기</button>
+          </form>
+        </div>
+
+        <template v-else>
+          <div class="controls">
+            <form class="url-form url-form--inline" @submit.prevent="void loadFromUrl()">
+              <input
+                v-model="imageUrlInput"
+                type="url"
+                inputmode="url"
+                placeholder="이미지 URL"
+                :disabled="busy"
+                aria-label="이미지 URL"
+              />
+              <button type="submit" :disabled="busy">URL</button>
+            </form>
+            <label class="field field--mode">
+              <span>모드</span>
+              <select v-model="mode" :disabled="busy">
+                <option value="threshold">전체 유사색 (글자 구멍 포함)</option>
+                <option value="flood">바깥만 (모서리 연결)</option>
+              </select>
+            </label>
+            <label class="field">
+              <span class="field__row">
+                허용치
+                <em>{{ tolerance }}</em>
+              </span>
+              <input
+                type="range"
+                min="0"
+                max="100"
+                step="1"
+                :value="tolerance"
+                :disabled="busy"
+                @input="
+                  tolerance = Number(($event.target as HTMLInputElement).value)
+                "
+                @change="void processImage()"
+              />
+            </label>
+            <label class="field">
+              <span class="field__row">
+                가장자리
+                <em>{{ feather }}</em>
+              </span>
+              <input
+                type="range"
+                min="0"
+                max="100"
+                step="1"
+                :value="feather"
+                :disabled="busy"
+                @input="
+                  feather = Number(($event.target as HTMLInputElement).value)
+                "
+                @change="void processImage()"
+              />
+            </label>
+            <div v-if="background" class="swatch" title="추정 배경색">
+              <span class="swatch__chip" :style="{ background: bgCss }" />
+              <span>배경 {{ bgCss }}</span>
+            </div>
+            <button
+              type="button"
+              class="btn-primary"
+              :disabled="busy || !resultUrl"
+              @click="exportPng"
+            >
+              PNG 저장
+            </button>
+          </div>
+
+          <div class="panes">
+            <section class="pane">
+              <h2>원본</h2>
+              <div class="frame">
+                <img :src="sourceUrl!" alt="원본" />
+              </div>
+            </section>
+            <section class="pane">
+              <h2>결과</h2>
+              <div class="frame frame--checker">
+                <img v-if="resultUrl" :src="resultUrl" alt="배경 제거 결과" />
+                <p v-else class="muted">처리 중…</p>
+              </div>
+            </section>
+          </div>
+        </template>
+
+        <div
+          v-if="dropActive && hasImage"
+          class="drop-overlay"
+          aria-hidden="true"
+        >
+          이미지를 놓아 바꾸기
+        </div>
+      </main>
+    </div>
+  </AppShell>
+</template>
+
+<style scoped>
+.bg-page {
+  flex: 1;
+  display: flex;
+  flex-direction: column;
+  min-height: 0;
+  height: 100%;
+  background: var(--canvas);
+}
+
+.workspace {
+  position: relative;
+  flex: 1;
+  min-height: 0;
+  overflow: auto;
+  padding: 0.85rem;
+}
+
+.empty {
+  height: 100%;
+  min-height: min(60vh, 28rem);
+  display: grid;
+  place-content: center;
+  justify-items: center;
+  gap: 0.75rem;
+  text-align: center;
+  color: var(--ink);
+  border: 1px dashed transparent;
+  border-radius: 6px;
+  padding: 1.25rem;
+}
+
+.empty.is-drop-active {
+  border-color: var(--accent);
+  background: var(--accent-soft);
+}
+
+.empty p {
+  margin: 0;
+  max-width: 28rem;
+  color: var(--muted);
+  font-size: 0.92rem;
+  line-height: 1.45;
+}
+
+.btn-primary {
+  min-height: 2.5rem;
+  border: 1px solid var(--accent);
+  border-radius: 4px;
+  padding: 0.4rem 0.9rem;
+  background: var(--accent-soft);
+  color: var(--ink);
+  font: inherit;
+  font-weight: 600;
+  cursor: pointer;
+}
+
+.btn-primary:disabled {
+  opacity: 0.5;
+  cursor: default;
+}
+
+.url-form {
+  display: flex;
+  flex-wrap: wrap;
+  gap: 0.4rem;
+  width: min(100%, 28rem);
+  margin-top: 0.25rem;
+}
+
+.url-form input {
+  flex: 1 1 12rem;
+  min-height: 2.5rem;
+  border: 1px solid var(--border);
+  border-radius: 4px;
+  padding: 0.35rem 0.55rem;
+  background: var(--canvas);
+  color: var(--ink);
+  font: inherit;
+}
+
+.url-form button {
+  min-height: 2.5rem;
+  border: 1px solid var(--border);
+  border-radius: 4px;
+  padding: 0.35rem 0.75rem;
+  background: var(--surface);
+  color: var(--ink);
+  font: inherit;
+  cursor: pointer;
+}
+
+.url-form button:disabled {
+  opacity: 0.5;
+  cursor: default;
+}
+
+.url-form--inline {
+  width: auto;
+  flex: 1 1 16rem;
+  margin-top: 0;
+  align-items: end;
+}
+
+.url-form--inline input {
+  min-height: 2.25rem;
+}
+
+.url-form--inline button {
+  min-height: 2.25rem;
+}
+
+.controls {
+  display: flex;
+  flex-wrap: wrap;
+  align-items: end;
+  gap: 0.75rem 1rem;
+  margin-bottom: 0.85rem;
+  padding: 0.65rem 0.75rem;
+  border: 1px solid var(--border);
+  border-radius: 6px;
+  background: var(--surface);
+}
+
+.field {
+  display: grid;
+  gap: 0.3rem;
+  min-width: 10rem;
+  flex: 1 1 12rem;
+  font-size: 0.86rem;
+}
+
+.field--mode {
+  flex: 0 1 16rem;
+}
+
+.field__row {
+  display: flex;
+  justify-content: space-between;
+  gap: 0.5rem;
+}
+
+.field__row em {
+  font-style: normal;
+  font-variant-numeric: tabular-nums;
+  color: var(--muted);
+}
+
+.field select,
+.field input[type='range'] {
+  width: 100%;
+  accent-color: var(--accent);
+}
+
+.field select {
+  min-height: 2.25rem;
+  border: 1px solid var(--border);
+  border-radius: 4px;
+  padding: 0.3rem 0.45rem;
+  background: var(--canvas);
+  color: var(--ink);
+  font: inherit;
+}
+
+.swatch {
+  display: inline-flex;
+  align-items: center;
+  gap: 0.4rem;
+  min-height: 2.25rem;
+  font-size: 0.8rem;
+  color: var(--muted);
+}
+
+.swatch__chip {
+  width: 1.1rem;
+  height: 1.1rem;
+  border-radius: 3px;
+  border: 1px solid var(--border);
+}
+
+.panes {
+  display: grid;
+  grid-template-columns: repeat(2, minmax(0, 1fr));
+  gap: 0.85rem;
+  align-items: start;
+}
+
+.pane {
+  min-width: 0;
+  overflow: auto;
+}
+
+.pane h2 {
+  margin: 0 0 0.45rem;
+  font-size: 0.9rem;
+}
+
+.frame {
+  display: inline-block;
+  width: fit-content;
+  max-width: 100%;
+  padding: 0.75rem;
+  border: 1px solid var(--border);
+  border-radius: 6px;
+  background: var(--surface);
+  overflow: auto;
+  vertical-align: top;
+  line-height: 0;
+}
+
+.frame--checker {
+  background-color: #c8c8c8;
+  background-image:
+    linear-gradient(45deg, #efefef 25%, transparent 25%),
+    linear-gradient(-45deg, #efefef 25%, transparent 25%),
+    linear-gradient(45deg, transparent 75%, #efefef 75%),
+    linear-gradient(-45deg, transparent 75%, #efefef 75%);
+  background-size: 20px 20px;
+  background-position:
+    0 0,
+    0 10px,
+    10px -10px,
+    -10px 0;
+}
+
+.frame img {
+  display: block;
+  width: auto;
+  height: auto;
+  max-width: none;
+  max-height: none;
+}
+
+.muted {
+  margin: 0;
+  color: var(--muted);
+}
+
+.drop-overlay {
+  position: absolute;
+  inset: 0.75rem;
+  z-index: 20;
+  display: grid;
+  place-items: center;
+  border: 2px dashed var(--accent);
+  border-radius: 8px;
+  background: color-mix(in srgb, var(--accent-soft) 88%, transparent);
+  color: var(--ink);
+  font-weight: 650;
+  pointer-events: none;
+}
+
+.viewer-message {
+  margin: 0;
+  padding: 0.45rem 0.85rem;
+  border-bottom: 1px solid var(--border);
+  background: var(--surface);
+  color: var(--ink);
+  font-size: 0.86rem;
+}
+
+.viewer-message--error {
+  color: #b42318;
+  background: color-mix(in srgb, #b42318 10%, var(--surface));
+}
+
+.sr-only {
+  position: absolute;
+  width: 1px;
+  height: 1px;
+  padding: 0;
+  margin: -1px;
+  overflow: hidden;
+  clip: rect(0, 0, 0, 0);
+  white-space: nowrap;
+  border: 0;
+}
+
+@media (max-width: 900px) {
+  .panes {
+    grid-template-columns: 1fr;
+  }
+
+  .controls {
+    align-items: stretch;
+  }
+
+  .controls .btn-primary {
+    width: 100%;
+  }
+}
+</style>