diff --git a/frontend/apps/main/src/features/conversation/message/MessageBubble.vue b/frontend/apps/main/src/features/conversation/message/MessageBubble.vue
index 562db8d8..9c17f797 100644
--- a/frontend/apps/main/src/features/conversation/message/MessageBubble.vue
+++ b/frontend/apps/main/src/features/conversation/message/MessageBubble.vue
@@ -77,7 +77,7 @@
                 :html="sanitizedContent"
                 :allowedSchemas="['cid', 'https', 'http', 'mailto']"
                 :allowed-css-properties="extendedCssProperties"
-                class="mb-1 native-html whitespace-pre-wrap break-words"
+                class="mb-1 native-html break-words"
                 :class="{ 'mb-3': message.attachments.length > 0 }"
               />
             </div>
@@ -205,6 +205,7 @@ import BubbleAttachmentPreview from '@main/features/conversation/message/attachm
 import MessageEnvelope from './MessageEnvelope.vue'
 import CSATResponseDisplay from './CSATResponseDisplay.vue'
 import api from '@main/api'
+import { containsQuoteMarkers } from '@shared-ui/utils/quotedContent.js'
 
 const extendedCssProperties = [...allowedCssProperties, 'transform', 'transform-origin']
 
@@ -305,7 +306,7 @@ const retryMessage = (msg) => {
 
 const showQuotedText = ref(false)
 const hasQuotedContent = computed(
-  () => !isOutgoing.value && sanitizedContent.value.includes('<blockquote')
+  () => !isOutgoing.value && containsQuoteMarkers(sanitizedContent.value)
 )
 const toggleQuote = () => {
   showQuotedText.value = !showQuotedText.value
diff --git a/frontend/apps/main/src/utils/quotedContent.test.js b/frontend/apps/main/src/utils/quotedContent.test.js
new file mode 100644
index 00000000..42984fe9
--- /dev/null
+++ b/frontend/apps/main/src/utils/quotedContent.test.js
@@ -0,0 +1,63 @@
+import { describe, test, expect } from 'vitest'
+import { containsQuoteMarkers } from '@shared-ui/utils/quotedContent.js'
+
+describe('containsQuoteMarkers', () => {
+  test('returns false for null', () => {
+    expect(containsQuoteMarkers(null)).toBe(false)
+  })
+
+  test('returns false for undefined', () => {
+    expect(containsQuoteMarkers(undefined)).toBe(false)
+  })
+
+  test('returns false for empty string', () => {
+    expect(containsQuoteMarkers('')).toBe(false)
+  })
+
+  test('returns false for plain HTML with no quote', () => {
+    expect(containsQuoteMarkers('<p>Hello world</p><div>thanks</div>')).toBe(false)
+  })
+
+  test('detects <blockquote> (Gmail/Apple/Thunderbird)', () => {
+    expect(containsQuoteMarkers('<blockquote>previous</blockquote>')).toBe(true)
+  })
+
+  test('detects <blockquote> with attributes', () => {
+    expect(containsQuoteMarkers('<blockquote type="cite" class="gmail_quote">x</blockquote>'))
+      .toBe(true)
+  })
+
+  test('detects Outlook Web appendonsend marker', () => {
+    expect(containsQuoteMarkers('<div id="appendonsend"></div>')).toBe(true)
+  })
+
+  test('detects Outlook divRplyFwdMsg marker', () => {
+    expect(containsQuoteMarkers('<div id="divRplyFwdMsg" dir="ltr">From:</div>')).toBe(true)
+  })
+
+  test('detects Outlook for Mac OLK_SRC_BODY_SECTION marker', () => {
+    expect(containsQuoteMarkers('<div id="OLK_SRC_BODY_SECTION">body</div>')).toBe(true)
+  })
+
+  test('detects legacy Outlook OutlookMessageHeader class', () => {
+    expect(containsQuoteMarkers('<div class="OutlookMessageHeader">x</div>')).toBe(true)
+  })
+
+  test('detects real Hotmail reply payload', () => {
+    const html = `<div class="elementToProof">Quoted reply!</div>
+      <div id="appendonsend"></div>
+      <hr style="display:inline-block;width:98%" tabindex="-1">
+      <div id="divRplyFwdMsg" dir="ltr"><font face="Calibri, sans-serif">From: Libredesk
+      Sent: 17 May 2026 18:12</font></div>
+      <div>Original message body</div>`
+    expect(containsQuoteMarkers(html)).toBe(true)
+  })
+
+  test('does not match marker word in plain prose', () => {
+    expect(containsQuoteMarkers('I love the appendonsend feature in Outlook')).toBe(false)
+  })
+
+  test('does not match if id uses single quotes (edge case - Outlook always emits double)', () => {
+    expect(containsQuoteMarkers(`<div id='appendonsend'></div>`)).toBe(false)
+  })
+})
diff --git a/frontend/apps/widget/src/components/ChatMessages.vue b/frontend/apps/widget/src/components/ChatMessages.vue
index 4c80e1f7..b8b249b4 100644
--- a/frontend/apps/widget/src/components/ChatMessages.vue
+++ b/frontend/apps/widget/src/components/ChatMessages.vue
@@ -160,6 +160,7 @@ import MessageAttachment from './MessageAttachment.vue'
 import CSATMessageBubble from './CSATMessageBubble.vue'
 import { TypingIndicator } from '@shared-ui/components/TypingIndicator'
 import { Spinner } from '@shared-ui/components/ui/spinner'
+import { containsQuoteMarkers } from '@shared-ui/utils/quotedContent.js'
 
 const extendedCssProperties = [...allowedCssProperties, 'transform', 'transform-origin']
 
@@ -187,9 +188,7 @@ const getMessageTime = (timestamp) => {
   return useRelativeTime(new Date(timestamp)).value
 }
 
-const hasQuotedContent = (content) => {
-  return content && content.includes('<blockquote')
-}
+const hasQuotedContent = (content) => containsQuoteMarkers(content)
 
 const isQuotedTextVisible = (messageUuid) => {
   return quotedTextState.value[messageUuid] || false
diff --git a/frontend/shared-ui/assets/styles/main.scss b/frontend/shared-ui/assets/styles/main.scss
index b0aa1364..e59622c9 100644
--- a/frontend/shared-ui/assets/styles/main.scss
+++ b/frontend/shared-ui/assets/styles/main.scss
@@ -296,7 +296,21 @@
 }
 
 .hide-quoted-text {
-  blockquote {
+  // Selectors below use attribute-suffix matching because vue-letter
+  // prefixes every id/class with a random "msg_XYZ_" at render time, so
+  // raw "#appendonsend" would never match.
+  // Outlook/Hotmail emit a marker with the quoted history as trailing
+  // siblings (no wrapping element), so we hide the marker AND everything
+  // after it. Outlook always top-posts, so trailing siblings are quote.
+  blockquote,
+  [id$="_divRplyFwdMsg"],
+  [id$="_divRplyFwdMsg"] ~ *,
+  [id$="_appendonsend"],
+  [id$="_appendonsend"] ~ *,
+  [id$="_OLK_SRC_BODY_SECTION"],
+  [id$="_OLK_SRC_BODY_SECTION"] ~ *,
+  [class*="_OutlookMessageHeader"],
+  [class*="_OutlookMessageHeader"] ~ * {
     @apply hidden;
   }
 }
diff --git a/frontend/shared-ui/utils/quotedContent.js b/frontend/shared-ui/utils/quotedContent.js
new file mode 100644
index 00000000..9ca51c93
--- /dev/null
+++ b/frontend/shared-ui/utils/quotedContent.js
@@ -0,0 +1,19 @@
+// Runs against the RAW HTML stored on the message - before vue-letter
+// renders. vue-letter prefixes every id/class with a random "msg_XYZ_" at
+// render time, so any CSS that needs to match the rendered DOM must use
+// attribute-suffix selectors (see .hide-quoted-text in main.scss).
+//
+// Scope: <blockquote> covers Gmail/Apple/Thunderbird. The id/class markers
+// below cover the Microsoft variants (Outlook desktop/web/mac, Hotmail).
+export const QUOTE_MARKERS = [
+  '<blockquote',
+  'id="divRplyFwdMsg"',
+  'id="appendonsend"',
+  'id="OLK_SRC_BODY_SECTION"',
+  'class="OutlookMessageHeader"'
+]
+
+export const containsQuoteMarkers = (html) => {
+  if (!html) return false
+  return QUOTE_MARKERS.some((marker) => html.includes(marker))
+}