diff --git a/openless-all/app/scripts/windows-capsule-acrylic-contract.test.mjs b/openless-all/app/scripts/windows-capsule-acrylic-contract.test.mjs
new file mode 100644
index 00000000..da07fef9
--- /dev/null
+++ b/openless-all/app/scripts/windows-capsule-acrylic-contract.test.mjs
@@ -0,0 +1,53 @@
+import { readFile } from 'node:fs/promises';
+
+function assertMatch(source, pattern, name) {
+  if (!pattern.test(source)) {
+    throw new Error(`${name}: pattern ${pattern} not found`);
+  }
+}
+
+function assertNotMatch(source, pattern, name) {
+  if (pattern.test(source)) {
+    throw new Error(`${name}: forbidden pattern ${pattern} found`);
+  }
+}
+
+const libRs = await readFile(new URL('../src-tauri/src/lib.rs', import.meta.url), 'utf-8');
+const capsuleTsx = await readFile(new URL('../src/components/Capsule.tsx', import.meta.url), 'utf-8');
+const capsuleLayoutTs = await readFile(new URL('../src/lib/capsuleLayout.ts', import.meta.url), 'utf-8');
+
+assertNotMatch(
+  libRs,
+  /apply_acrylic\(&capsule,/,
+  'windows capsule must not use window-vibrancy Acrylic because it paints a rectangular grey host on Win11',
+);
+
+assertNotMatch(
+  libRs,
+  /DwmEnableBlurBehindWindow|DWMWA_SYSTEMBACKDROP_TYPE|SetWindowRgn/,
+  'windows capsule must not use HWND-level DWM material or native regions; the DOM pill owns the visible shape',
+);
+
+assertMatch(
+  libRs,
+  /apply_acrylic\(&qa,\s*Some\(\(30,\s*32,\s*38,\s*140\)\)\)/,
+  'windows QA window may keep Acrylic because its panel fills the native host',
+);
+
+assertMatch(
+  capsuleLayoutTs,
+  /return \{ width: 180, height: 44, textWidth: 88, boxSizing: 'border-box' \};[\s\S]*?const horizontalInset = 12;[\s\S]*?width: 220,[\s\S]*?height: translationActive \? 118 : 84,[\s\S]*?bottomInset: 12,/,
+  'windows capsule should keep the original compact DOM pill inside a transparent native host',
+);
+
+assertMatch(
+  capsuleTsx,
+  /const useBackdrop = os !== 'win';[\s\S]*?background: os === 'win' \? 'rgba\(255, 255, 255, 0\.96\)' : 'rgba\(255, 255, 255, 0\.85\)'/,
+  'windows capsule pill should use an opaque DOM surface instead of WebView2 backdrop-filter over a transparent host',
+);
+
+assertMatch(
+  capsuleTsx,
+  /return\s*\(\s*<div\s*style=\{\{[\s\S]*?width:\s*'100%',[\s\S]*?height:\s*'100%',[\s\S]*?paddingLeft:\s*hostMetrics\.horizontalInset,[\s\S]*?paddingRight:\s*hostMetrics\.horizontalInset,[\s\S]*?background:\s*'transparent'/,
+  'capsule host should remain transparent outside the visible pill',
+);
diff --git a/openless-all/app/scripts/windows-ui-config.test.mjs b/openless-all/app/scripts/windows-ui-config.test.mjs
index 4d9ddb61..cf81e2b6 100644
--- a/openless-all/app/scripts/windows-ui-config.test.mjs
+++ b/openless-all/app/scripts/windows-ui-config.test.mjs
@@ -108,7 +108,11 @@ if (!/export function getCapsuleHostMetrics\(\s*os: OS,\s*translationActive: boo
   throw new Error('capsule layout should define explicit host metrics separate from the visible pill metrics');
 }
 
-if (!/if \(os === 'win'\)\s*\{[\s\S]*?const horizontalInset = 12;[\s\S]*?const pill = getCapsulePillMetrics\(os\);[\s\S]*?width: pill\.width \+ horizontalInset \* 2,[\s\S]*?height: translationActive \? 118 : 84,[\s\S]*?horizontalInset,[\s\S]*?bottomInset: 12,[\s\S]*?badgeGap: 8,[\s\S]*?boxSizing: 'border-box',[\s\S]*?\}/.test(capsuleLayoutTs)) {
+if (!/if \(os === 'win'\)\s*\{[\s\S]*?return \{ width: 180, height: 44, textWidth: 88, boxSizing: 'border-box' \};[\s\S]*?\}/.test(capsuleLayoutTs)) {
+  throw new Error('windows capsule should keep the original compact visible pill metrics');
+}
+
+if (!/if \(os === 'win'\)\s*\{[\s\S]*?const horizontalInset = 12;[\s\S]*?width: 220,[\s\S]*?height: translationActive \? 118 : 84,[\s\S]*?horizontalInset,[\s\S]*?bottomInset: 12,[\s\S]*?badgeGap: 8,[\s\S]*?boxSizing: 'border-box',[\s\S]*?\}/.test(capsuleLayoutTs)) {
   throw new Error('windows capsule host metrics should leave room for shadow and badge geometry');
 }
 
@@ -132,7 +136,7 @@ if (!/hostMetrics\.bottomInset \+ metrics\.height \+ hostMetrics\.badgeGap/.test
   throw new Error('windows translation badge should anchor from the shared host inset instead of a fixed center-based offset');
 }
 
-if (!/#\[cfg\(target_os = "windows"\)\][\s\S]*?const WINDOWS_CAPSULE_PILL_WIDTH: f64 = 196\.0;[\s\S]*?const WINDOWS_CAPSULE_SIDE_INSET: f64 = 12\.0;[\s\S]*?width: WINDOWS_CAPSULE_PILL_WIDTH \+ WINDOWS_CAPSULE_SIDE_INSET \* 2\.0,[\s\S]*?height: if translation_active \{ 118\.0 \} else \{ 84\.0 \},[\s\S]*?bottom_inset: 12\.0,/.test(libRs)) {
+if (!/#\[cfg\(target_os = "windows"\)\]\s*\{[\s\S]*?const WINDOWS_CAPSULE_SIDE_INSET: f64 = 12\.0;[\s\S]*?width: 220\.0,[\s\S]*?height: if translation_active \{ 118\.0 \} else \{ 84\.0 \},[\s\S]*?bottom_inset: WINDOWS_CAPSULE_SIDE_INSET,/.test(libRs)) {
   throw new Error('windows runtime capsule bounds should leave room for the native shadow while keeping a fixed visual pill');
 }
 
diff --git a/openless-all/app/src-tauri/src/lib.rs b/openless-all/app/src-tauri/src/lib.rs
index 4cee867a..5dd120f0 100644
--- a/openless-all/app/src-tauri/src/lib.rs
+++ b/openless-all/app/src-tauri/src/lib.rs
@@ -129,19 +129,9 @@ pub fn run() {
                 if let Err(e) = position_capsule_bottom_center(&capsule, false) {
                     log::warn!("[capsule] position failed: {e}");
                 }
-                // Windows 上 transparent:true 让窗口对桌面完全透明，Webview2 的
-                // backdrop-filter 只能模糊 DOM 内部，模糊不到 OS 桌面 → 胶囊背景
-                // 看起来就是「透到桌面」。这里给 Win10/Win11 都支持的 Acrylic 做兜底，
-                // 让 OS 提供毛玻璃材质，胶囊 rgba(255,255,255,0.85) 上面再叠 DOM 模糊。
-                // 失败不阻塞（老 Win10 / Win7 上 Acrylic 不可用），仅 warn。
-                #[cfg(target_os = "windows")]
-                {
-                    use window_vibrancy::apply_acrylic;
-                    // 中性偏冷的浅灰半透，与胶囊白底叠合后保持可读性。
-                    if let Err(e) = apply_acrylic(&capsule, Some((30, 32, 38, 140))) {
-                        log::warn!("[capsule] acrylic failed: {e}");
-                    }
-                }
+                // Keep the Windows capsule host fully transparent. The native host is larger
+                // than the visible pill to reserve shadow, badge, and animation room; applying
+                // a HWND-level material here paints those transparent margins as a gray box.
                 let _ = capsule.hide();
             }
 
@@ -155,9 +145,8 @@ pub fn run() {
                 }
                 #[cfg(target_os = "macos")]
                 make_qa_window_draggable_macos(&qa);
-                // 同 capsule：Windows 下 QA 浮窗也走 Acrylic 兜底。QA 面板自身
-                // 已经把 alpha 拉到 0.97（QaPanel.tsx:623），主要是防止 0.03 缝隙
-                // 透到桌面、以及 Win10 上完全无毛玻璃感的兜底。
+                // QA fills its native host, so Windows Acrylic remains a useful fallback here.
+                // Capsule is different: its host has transparent margins around a smaller pill.
                 #[cfg(target_os = "windows")]
                 {
                     use window_vibrancy::apply_acrylic;
@@ -1223,14 +1212,13 @@ struct CapsuleWindowBounds {
 fn capsule_window_bounds(translation_active: bool) -> CapsuleWindowBounds {
     #[cfg(target_os = "windows")]
     {
-        const WINDOWS_CAPSULE_PILL_WIDTH: f64 = 196.0;
         const WINDOWS_CAPSULE_SIDE_INSET: f64 = 12.0;
         CapsuleWindowBounds {
-            // Keep the existing Windows hitbox width, but express it as
-            // pill width (196) + symmetric 12px side insets for shadow room.
-            width: WINDOWS_CAPSULE_PILL_WIDTH + WINDOWS_CAPSULE_SIDE_INSET * 2.0,
+            // Keep the existing Windows hitbox width while reserving transparent
+            // margins for the DOM pill shadow and translation badge animation.
+            width: 220.0,
             height: if translation_active { 118.0 } else { 84.0 },
-            bottom_inset: 12.0,
+            bottom_inset: WINDOWS_CAPSULE_SIDE_INSET,
         }
     }
 
diff --git a/openless-all/app/src/components/Capsule.tsx b/openless-all/app/src/components/Capsule.tsx
index 283ce712..1cb4aed6 100644
--- a/openless-all/app/src/components/Capsule.tsx
+++ b/openless-all/app/src/components/Capsule.tsx
@@ -244,7 +244,7 @@ function Pill({ os, state, level, insertedChars, message, onCancel, onConfirm }:
   const ambient = state === 'recording' ? Math.min(1, Math.max(0, level)) : 0;
   const scale = os === 'win' ? 1 : 1 + ambient * 0.018;
   const shadowAlpha = 0.20 + ambient * 0.10;
-  const useBackdrop = true;
+  const useBackdrop = os !== 'win';
 
   return (
     <div
@@ -258,10 +258,10 @@ function Pill({ os, state, level, insertedChars, message, onCancel, onConfirm }:
         height: metrics.height,
         boxSizing: metrics.boxSizing,
         borderRadius: 999,
-        background: 'rgba(255, 255, 255, 0.85)',
+        background: os === 'win' ? 'rgba(255, 255, 255, 0.96)' : 'rgba(255, 255, 255, 0.85)',
         backdropFilter: useBackdrop ? 'blur(28px) saturate(180%)' : 'none',
         WebkitBackdropFilter: useBackdrop ? 'blur(28px) saturate(180%)' : 'none',
-        border: '1px solid rgba(255, 255, 255, 0.55)',
+        border: os === 'win' ? '1px solid rgba(255, 255, 255, 0.78)' : '1px solid rgba(255, 255, 255, 0.55)',
         boxShadow: os === 'win'
           ? `0 10px 24px -14px rgba(0, 0, 0, ${(0.24 + ambient * 0.06).toFixed(3)}), 0 0 0 0.5px rgba(0, 0, 0, 0.08), inset 0 0.5px 0 rgba(255, 255, 255, 0.55)`
           : `0 18px 50px -10px rgba(0, 0, 0, ${shadowAlpha.toFixed(3)}), 0 0 0 0.5px rgba(0, 0, 0, 0.08), inset 0 0.5px 0 rgba(255, 255, 255, 0.55)`,
diff --git a/openless-all/app/src/lib/capsuleLayout.test.ts b/openless-all/app/src/lib/capsuleLayout.test.ts
index c4a0f6c0..0f07749f 100644
--- a/openless-all/app/src/lib/capsuleLayout.test.ts
+++ b/openless-all/app/src/lib/capsuleLayout.test.ts
@@ -11,9 +11,9 @@ function assertEqual<T>(actual: T, expected: T, name: string) {
 }
 
 const winMetrics = getCapsulePillMetrics('win');
-assertEqual(winMetrics.width, 196, 'windows capsule widens pill');
-assertEqual(winMetrics.height, 52, 'windows capsule increases pill height');
-assertEqual(winMetrics.textWidth, 104, 'windows capsule keeps side controls clear');
+assertEqual(winMetrics.width, 180, 'windows capsule keeps original pill width');
+assertEqual(winMetrics.height, 44, 'windows capsule keeps original pill height');
+assertEqual(winMetrics.textWidth, 88, 'windows capsule keeps original text slot');
 assertEqual(winMetrics.boxSizing, 'border-box', 'windows capsule pill width is an outer border-box metric');
 
 const winHost = getCapsuleHostMetrics('win', false);
@@ -22,14 +22,19 @@ assertEqual(winHost.height, 84, 'windows capsule host keeps regular height');
 assertEqual(winHost.horizontalInset, 12, 'windows capsule host keeps symmetric shadow insets');
 assertEqual(winHost.boxSizing, 'border-box', 'windows capsule host inset is reserved inside the native width');
 assertEqual(
-  winHost.width,
-  winMetrics.width + winHost.horizontalInset * 2,
-  'windows capsule host width derives from pill width plus symmetric side insets',
+  winHost.width - winHost.horizontalInset * 2,
+  196,
+  'windows capsule host leaves extra centering room around the original pill',
+);
+assertEqual(
+  winHost.width - winHost.horizontalInset * 2 - winMetrics.width,
+  16,
+  'windows capsule host keeps the visible pill compact inside the transparent host',
 );
 assertEqual(
-  winHost.width - winHost.horizontalInset * 2,
   winMetrics.width,
-  'windows capsule host keeps the visible pill width after reserving side insets',
+  180,
+  'windows capsule pill is independent from the host hitbox width',
 );
 
 const winHostWithTranslation = getCapsuleHostMetrics('win', true);
diff --git a/openless-all/app/src/lib/capsuleLayout.ts b/openless-all/app/src/lib/capsuleLayout.ts
index cf116eb6..5663552a 100644
--- a/openless-all/app/src/lib/capsuleLayout.ts
+++ b/openless-all/app/src/lib/capsuleLayout.ts
@@ -26,7 +26,7 @@ export interface CapsuleMessageLayout {
 export function getCapsulePillMetrics(os: OS): CapsulePillMetrics {
   if (os === 'win') {
     // Windows metrics describe the visible outer footprint of the pill.
-    // 与 macOS pill 接近以保持视觉密度一致；保留 ~4-5% 余量适配 Windows 字体 metrics。
+    // Keep the original compact capsule shape; the native host owns only transparent room.
     return { width: 180, height: 44, textWidth: 88, boxSizing: 'border-box' };
   }
 
@@ -41,9 +41,8 @@ export function getCapsuleHostMetrics(
 ): CapsuleHostMetrics {
   if (os === 'win') {
     const horizontalInset = 12;
-    const pill = getCapsulePillMetrics(os);
     return {
-      width: pill.width + horizontalInset * 2,
+      width: 220,
       height: translationActive ? 118 : 84,
       horizontalInset,
       bottomInset: 12,