diff --git a/frontend/src/components/common/AnnouncementBell.vue b/frontend/src/components/common/AnnouncementBell.vue
index cfbd62a0b8..e80e449f28 100644
--- a/frontend/src/components/common/AnnouncementBell.vue
+++ b/frontend/src/components/common/AnnouncementBell.vue
@@ -322,6 +322,7 @@ import { useAnnouncementStore } from '@/stores/announcements'
import { formatRelativeTime, formatRelativeWithDateTime } from '@/utils/format'
import type { UserAnnouncement } from '@/types'
import Icon from '@/components/icons/Icon.vue'
+import '@/styles/announcement-markdown.css'
const { t } = useI18n()
const appStore = useAppStore()
@@ -471,120 +472,3 @@ watch(
background: linear-gradient(to bottom, #6b7280, #4b5563);
}
-
-
diff --git a/frontend/src/components/common/AnnouncementPopup.vue b/frontend/src/components/common/AnnouncementPopup.vue
index e26d9ee30b..e0a0f23125 100644
--- a/frontend/src/components/common/AnnouncementPopup.vue
+++ b/frontend/src/components/common/AnnouncementPopup.vue
@@ -90,6 +90,7 @@ import { marked } from 'marked'
import DOMPurify from 'dompurify'
import { useAnnouncementStore } from '@/stores/announcements'
import { formatRelativeWithDateTime } from '@/utils/format'
+import '@/styles/announcement-markdown.css'
const { t } = useI18n()
const announcementStore = useAnnouncementStore()
diff --git a/frontend/src/components/common/__tests__/AnnouncementPopup.spec.ts b/frontend/src/components/common/__tests__/AnnouncementPopup.spec.ts
new file mode 100644
index 0000000000..2603b8ef4f
--- /dev/null
+++ b/frontend/src/components/common/__tests__/AnnouncementPopup.spec.ts
@@ -0,0 +1,72 @@
+import { afterEach, beforeEach, describe, expect, it, vi } from 'vitest'
+import { mount } from '@vue/test-utils'
+import { createPinia, setActivePinia } from 'pinia'
+import { readFileSync } from 'node:fs'
+import { resolve } from 'node:path'
+
+import AnnouncementPopup from '../AnnouncementPopup.vue'
+import { useAnnouncementStore } from '@/stores/announcements'
+
+const announcementMarkdownStyles = readFileSync(
+ resolve(process.cwd(), 'src/styles/announcement-markdown.css'),
+ 'utf8',
+)
+
+vi.mock('vue-i18n', async () => {
+ const actual = await vi.importActual('vue-i18n')
+ return {
+ ...actual,
+ useI18n: () => ({
+ t: (key: string) => key,
+ }),
+ }
+})
+
+describe('AnnouncementPopup', () => {
+ beforeEach(() => {
+ setActivePinia(createPinia())
+ })
+
+ afterEach(() => {
+ document.body.innerHTML = ''
+ document.body.style.overflow = ''
+ })
+
+ it('renders mixed Markdown and HTML inside the shared styled container', async () => {
+ const store = useAnnouncementStore()
+ store.currentPopup = {
+ id: 1,
+ title: 'Mixed content announcement',
+ content: [
+ '## Markdown heading',
+ '',
+ '',
+ '',
+ '',
+ '',
+ ].join('\n'),
+ notify_mode: 'popup',
+ created_at: '2026-07-24T07:30:00Z',
+ updated_at: '2026-07-24T07:30:00Z',
+ }
+
+ const wrapper = mount(AnnouncementPopup)
+ await wrapper.vm.$nextTick()
+
+ const content = document.body.querySelector('.markdown-body')
+ expect(content?.querySelector('h2')?.textContent).toBe('Markdown heading')
+ expect(content?.querySelector('h3')?.textContent).toBe('HTML heading')
+ expect(content?.querySelector('li')?.textContent).toBe('HTML list item')
+ expect(content?.querySelector('table td')?.textContent).toBe('OK')
+ expect(content?.querySelector('script')).toBeNull()
+
+ wrapper.unmount()
+ })
+
+ it.each(['h2', 'h3', 'ul', 'li', 'blockquote', 'table', 'th', 'td', 'code'])(
+ 'loads a shared style rule for mixed-content <%s> elements',
+ (element) => {
+ expect(announcementMarkdownStyles).toContain(`.markdown-body ${element}`)
+ },
+ )
+})
diff --git a/frontend/src/styles/announcement-markdown.css b/frontend/src/styles/announcement-markdown.css
new file mode 100644
index 0000000000..c5852b1113
--- /dev/null
+++ b/frontend/src/styles/announcement-markdown.css
@@ -0,0 +1,113 @@
+/* Shared rich-text styles for announcement popup and bell detail content. */
+.markdown-body {
+ @apply text-[15px] leading-[1.75];
+ @apply text-gray-700 dark:text-gray-300;
+}
+
+.markdown-body h1 {
+ @apply mb-6 mt-8 border-b border-gray-200 pb-3 text-3xl font-bold text-gray-900 dark:border-dark-600 dark:text-white;
+}
+
+.markdown-body h2 {
+ @apply mb-4 mt-7 border-b border-gray-100 pb-2 text-2xl font-bold text-gray-900 dark:border-dark-700 dark:text-white;
+}
+
+.markdown-body h3 {
+ @apply mb-3 mt-6 text-xl font-semibold text-gray-900 dark:text-white;
+}
+
+.markdown-body h4 {
+ @apply mb-2 mt-5 text-lg font-semibold text-gray-900 dark:text-white;
+}
+
+.markdown-body p {
+ @apply mb-4 leading-relaxed;
+}
+
+.markdown-body a {
+ @apply font-medium text-blue-600 underline decoration-blue-600/30 decoration-2 underline-offset-2 transition-all hover:decoration-blue-600 dark:text-blue-400 dark:decoration-blue-400/30 dark:hover:decoration-blue-400;
+}
+
+.markdown-body ul,
+.markdown-body ol {
+ @apply mb-4 ml-6 space-y-2;
+}
+
+.markdown-body ul {
+ @apply list-disc;
+}
+
+.markdown-body ol {
+ @apply list-decimal;
+}
+
+.markdown-body li {
+ @apply pl-2 leading-relaxed;
+}
+
+.markdown-body li::marker {
+ @apply text-blue-600 dark:text-blue-400;
+}
+
+.markdown-body blockquote {
+ @apply relative my-5 border-l-4 border-blue-500 bg-blue-50/50 py-3 pl-5 pr-4 italic text-gray-700 dark:border-blue-400 dark:bg-blue-900/10 dark:text-gray-300;
+}
+
+.markdown-body blockquote::before {
+ content: '"';
+ @apply absolute -left-1 top-0 font-serif text-5xl text-blue-500/20 dark:text-blue-400/20;
+}
+
+.markdown-body code {
+ @apply rounded-lg bg-gray-100 px-2 py-1 font-mono text-[13px] text-pink-600 dark:bg-dark-700 dark:text-pink-400;
+}
+
+.markdown-body pre {
+ @apply my-5 overflow-x-auto rounded-xl border border-gray-200 bg-gray-50 p-5 dark:border-dark-600 dark:bg-dark-900/50;
+}
+
+.markdown-body pre code {
+ @apply bg-transparent p-0 text-[13px] text-gray-800 dark:text-gray-200;
+}
+
+.markdown-body hr {
+ @apply my-8 border-0 border-t-2 border-gray-200 dark:border-dark-700;
+}
+
+.markdown-body table {
+ @apply mb-5 w-full overflow-hidden rounded-lg border border-gray-200 dark:border-dark-600;
+}
+
+.markdown-body th,
+.markdown-body td {
+ @apply border-b border-r border-gray-200 px-4 py-3 text-left dark:border-dark-600;
+}
+
+.markdown-body th:last-child,
+.markdown-body td:last-child {
+ @apply border-r-0;
+}
+
+.markdown-body tr:last-child td {
+ @apply border-b-0;
+}
+
+.markdown-body th {
+ @apply bg-gradient-to-br from-blue-50 to-indigo-50 font-semibold text-gray-900 dark:from-blue-900/20 dark:to-indigo-900/10 dark:text-white;
+}
+
+.markdown-body tbody tr {
+ @apply transition-colors hover:bg-gray-50 dark:hover:bg-dark-700/30;
+}
+
+.markdown-body img {
+ @apply my-5 max-w-full rounded-xl border border-gray-200 shadow-md dark:border-dark-600;
+}
+
+.markdown-body strong {
+ @apply font-semibold text-gray-900 dark:text-white;
+}
+
+.markdown-body em {
+ @apply italic text-gray-600 dark:text-gray-400;
+}