diff --git a/src-tauri/tauri.conf.json b/src-tauri/tauri.conf.json
index de1d0e21..97a040d4 100644
--- a/src-tauri/tauri.conf.json
+++ b/src-tauri/tauri.conf.json
@@ -33,6 +33,8 @@
         "connect-src": "'self' ipc: http://ipc.localhost ws://localhost:9710 ws://127.0.0.1:9710 ws://localhost:9711 ws://127.0.0.1:9711 https:",
         "img-src": "'self' asset: http://asset.localhost data: blob: https:",
         "style-src": "'self' 'unsafe-inline' https://fonts.googleapis.com",
+        "style-src-elem": "'self' 'nonce-tolaria-runtime-style' https://fonts.googleapis.com",
+        "style-src-attr": "'unsafe-inline'",
         "font-src": "'self' data: https://fonts.gstatic.com",
         "media-src": "'self' data: blob: https:",
         "object-src": "'none'"
diff --git a/src/components/Editor.test.tsx b/src/components/Editor.test.tsx
index 1e50ad21..78d8d3b7 100644
--- a/src/components/Editor.test.tsx
+++ b/src/components/Editor.test.tsx
@@ -1,7 +1,8 @@
 import { render as rtlRender, screen, fireEvent, act } from '@testing-library/react'
 import type { ComponentProps, PropsWithChildren, ReactElement } from 'react'
-import { describe, it, expect, vi } from 'vitest'
+import { beforeEach, describe, it, expect, vi } from 'vitest'
 import { formatShortcutDisplay } from '../hooks/appCommandCatalog'
+import { RUNTIME_STYLE_NONCE } from '../lib/runtimeStyleNonce'
 
 Object.defineProperty(window, 'matchMedia', {
   writable: true,
@@ -34,6 +35,9 @@ const mockEditor = vi.hoisted(() => ({
   focus: vi.fn(),
   setTextCursorPosition: vi.fn(),
 }))
+const blockNoteCreation = vi.hoisted(() => ({
+  options: [] as unknown[],
+}))
 
 // Mock BlockNote components
 vi.mock('@blocknote/core', () => ({
@@ -61,7 +65,10 @@ let capturedGetItems: ((query: string) => Promise<any[]>) | null = null
 vi.mock('@blocknote/react', () => ({
   createReactBlockSpec: () => () => ({}),
   createReactInlineContentSpec: () => ({ render: () => null }),
-  useCreateBlockNote: () => mockEditor,
+  useCreateBlockNote: (options: unknown) => {
+    blockNoteCreation.options.push(options)
+    return mockEditor
+  },
   FormattingToolbar: ({ children }: PropsWithChildren) => <>{children}</>,
   LinkToolbar: ({ children }: PropsWithChildren) => <>{children}</>,
   getFormattingToolbarItems: () => [],
@@ -210,6 +217,10 @@ function renderEditor(overrides: Partial<EditorComponentProps> = {}) {
 }
 
 describe('Editor', () => {
+  beforeEach(() => {
+    blockNoteCreation.options = []
+  })
+
   it('shows empty state when no tabs are open', () => {
     const quickOpenHint = formatShortcutDisplay({ display: '⌘P / ⌘O' })
     const newNoteHint = formatShortcutDisplay({ display: '⌘N' })
@@ -244,6 +255,19 @@ describe('Editor', () => {
     expect(screen.getByTestId('blocknote-view')).toBeInTheDocument()
   })
 
+  it('passes the runtime CSP style nonce into BlockNote and TipTap', () => {
+    renderEditor({
+      tabs: [mockTab],
+      activeTabPath: mockEntry.path,
+    })
+
+    expect(blockNoteCreation.options.at(-1)).toMatchObject({
+      _tiptapOptions: {
+        injectNonce: RUNTIME_STYLE_NONCE,
+      },
+    })
+  })
+
   it('disables native text assistance on the rich editor editable surface', () => {
     renderEditor({
       tabs: [mockTab],
diff --git a/src/components/Editor.tsx b/src/components/Editor.tsx
index ae971652..7ff9dddf 100644
--- a/src/components/Editor.tsx
+++ b/src/components/Editor.tsx
@@ -5,6 +5,7 @@ import '@blocknote/mantine/style.css'
 import 'katex/dist/katex.min.css'
 import { uploadImageFile } from '../hooks/useImageDrop'
 import { DEFAULT_AI_AGENT, type AiAgentId } from '../lib/aiAgents'
+import { RUNTIME_STYLE_NONCE } from '../lib/runtimeStyleNonce'
 import type { VaultEntry, GitCommit, NoteLayout, NoteStatus } from '../types'
 import type { NoteListItem } from '../utils/ai-context'
 import type { FrontmatterValue } from './Inspector'
@@ -177,6 +178,7 @@ function useEditorSetup({
   const editor = useCreateBlockNote({
     schema,
     uploadFile: (file: File) => uploadImageFile(file, vaultPathRef.current),
+    _tiptapOptions: { injectNonce: RUNTIME_STYLE_NONCE },
     extensions: [createArrowLigaturesExtension()],
   })
   useFilenameAutolinkGuard(editor)
diff --git a/src/components/SingleEditorView.test.tsx b/src/components/SingleEditorView.test.tsx
index eb260d15..48878bcb 100644
--- a/src/components/SingleEditorView.test.tsx
+++ b/src/components/SingleEditorView.test.tsx
@@ -2,6 +2,7 @@ import { act, fireEvent, render, screen } from '@testing-library/react'
 import { beforeEach, describe, expect, it, vi } from 'vitest'
 import type { ReactNode } from 'react'
 import type { VaultEntry } from '../types'
+import { RUNTIME_STYLE_NONCE } from '../lib/runtimeStyleNonce'
 
 const NOTE_DRAG_MIME = 'application/x-laputa-note-path'
 
@@ -11,6 +12,7 @@ const state = vi.hoisted(() => ({
   capturedSuggestionProps: {} as Record<string, Record<string, unknown>>,
   capturedImageDropArgs: null as null | Record<string, unknown>,
   capturedBlockNoteOnChange: null as null | (() => void),
+  capturedMantineGetStyleNonce: null as null | (() => string),
   hoverGuardMock: vi.fn(),
   imageDropState: { isDragOver: false },
   linkActivationMock: vi.fn(),
@@ -110,7 +112,16 @@ vi.mock('@mantine/core', async () => {
   const React = await vi.importActual<typeof import('react')>('react')
   return {
     MantineContext: React.createContext(null),
-    MantineProvider: ({ children }: { children?: ReactNode }) => <>{children}</>,
+    MantineProvider: ({
+      children,
+      getStyleNonce,
+    }: {
+      children?: ReactNode
+      getStyleNonce?: () => string
+    }) => {
+      state.capturedMantineGetStyleNonce = getStyleNonce ?? null
+      return <>{children}</>
+    },
   }
 })
 
@@ -277,6 +288,7 @@ describe('SingleEditorView', () => {
     state.capturedSuggestionProps = {}
     state.capturedImageDropArgs = null
     state.capturedBlockNoteOnChange = null
+    state.capturedMantineGetStyleNonce = null
     state.imageDropState.isDragOver = false
     state.wikilinkEntriesRef.current = []
     mockOpenExternalUrl.mockClear()
@@ -469,6 +481,18 @@ describe('SingleEditorView', () => {
     expect(screen.getByTestId('blocknote-view')).toHaveAttribute('data-mantine-color-scheme', 'dark')
   })
 
+  it('passes the runtime CSP style nonce to Mantine fallback style tags', () => {
+    render(
+      <SingleEditorView
+        editor={createEditor() as never}
+        entries={[makeEntry()]}
+        onNavigateWikilink={vi.fn()}
+      />,
+    )
+
+    expect(state.capturedMantineGetStyleNonce?.()).toBe(RUNTIME_STYLE_NONCE)
+  })
+
   it('defers rich-editor change propagation until IME composition ends', async () => {
     const editor = createEditor()
     const onChange = vi.fn()
diff --git a/src/components/SingleEditorView.tsx b/src/components/SingleEditorView.tsx
index 2cca2652..c579b733 100644
--- a/src/components/SingleEditorView.tsx
+++ b/src/components/SingleEditorView.tsx
@@ -27,6 +27,7 @@ import { filterPersonMentions, PERSON_MENTION_MIN_QUERY } from '../utils/personM
 import { attachClickHandlers, enrichSuggestionItems } from '../utils/suggestionEnrichment'
 import { openExternalUrl } from '../utils/url'
 import { observeNativeTextAssistanceDisabled } from '../lib/nativeTextAssistance'
+import { getRuntimeStyleNonce } from '../lib/runtimeStyleNonce'
 import { WikilinkSuggestionMenu, type WikilinkSuggestionItem } from './WikilinkSuggestionMenu'
 import type { VaultEntry } from '../types'
 import { _wikilinkEntriesRef } from './editorSchema'
@@ -91,6 +92,7 @@ function SharedContextBlockNoteView(props: React.ComponentProps<typeof BlockNote
     <MantineProvider
       // BlockNote scopes Mantine defaults under `.bn-mantine` instead of `:root`.
       withCssVariables={false}
+      getStyleNonce={getRuntimeStyleNonce}
       getRootElement={() => undefined}
     >
       {view}
diff --git a/src/hooks/useCodeMirror.test.ts b/src/hooks/useCodeMirror.test.ts
index 7e9f8c51..288f8c48 100644
--- a/src/hooks/useCodeMirror.test.ts
+++ b/src/hooks/useCodeMirror.test.ts
@@ -1,5 +1,7 @@
 import { describe, it, expect, vi, beforeEach, afterEach } from 'vitest'
 import { renderHook, act } from '@testing-library/react'
+import { EditorView } from '@codemirror/view'
+import { RUNTIME_STYLE_NONCE } from '../lib/runtimeStyleNonce'
 import { useCodeMirror, type CodeMirrorCallbacks } from './useCodeMirror'
 
 const noop = () => {}
@@ -31,6 +33,15 @@ describe('useCodeMirror', () => {
     expect(container.querySelector('.cm-editor')).toBeInTheDocument()
   })
 
+  it('tags generated CodeMirror style elements with the runtime CSP nonce', () => {
+    const ref = { current: container }
+    const { result } = renderHook(() =>
+      useCodeMirror(ref, 'hello world', noopCallbacks),
+    )
+
+    expect(result.current.current?.state.facet(EditorView.cspNonce)).toBe(RUNTIME_STYLE_NONCE)
+  })
+
   it('calls requestMeasure when laputa-zoom-change event fires', () => {
     const ref = { current: container }
     const { result } = renderHook(() =>
diff --git a/src/hooks/useCodeMirror.ts b/src/hooks/useCodeMirror.ts
index 084369bc..5dd5b150 100644
--- a/src/hooks/useCodeMirror.ts
+++ b/src/hooks/useCodeMirror.ts
@@ -4,6 +4,7 @@ import { EditorState } from '@codemirror/state'
 import { defaultKeymap, history, historyKeymap } from '@codemirror/commands'
 import { frontmatterHighlightPlugin, frontmatterHighlightTheme } from '../extensions/frontmatterHighlight'
 import { markdownLanguage } from '../extensions/markdownHighlight'
+import { RUNTIME_STYLE_NONCE } from '../lib/runtimeStyleNonce'
 import { resolveArrowLigatureInput } from '../utils/arrowLigatures'
 import { zoomCursorFix } from '../extensions/zoomCursorFix'
 import { nativeTextAssistanceDisabledAttributes } from '../lib/nativeTextAssistance'
@@ -145,6 +146,7 @@ export function useCodeMirror(
         keymap.of([...defaultKeymap, ...historyKeymap]),
         buildSaveKeymap(callbacksRef),
         buildBaseTheme(),
+        EditorView.cspNonce.of(RUNTIME_STYLE_NONCE),
         EditorView.contentAttributes.of(nativeTextAssistanceDisabledAttributes),
         markdownLanguage(),
         frontmatterHighlightTheme(),
diff --git a/src/lib/runtimeStyleNonce.ts b/src/lib/runtimeStyleNonce.ts
new file mode 100644
index 00000000..6ffb36fd
--- /dev/null
+++ b/src/lib/runtimeStyleNonce.ts
@@ -0,0 +1,6 @@
+export const RUNTIME_STYLE_NONCE = 'tolaria-runtime-style'
+export const RUNTIME_STYLE_NONCE_SOURCE = `'nonce-${RUNTIME_STYLE_NONCE}'`
+
+export function getRuntimeStyleNonce() {
+  return RUNTIME_STYLE_NONCE
+}
diff --git a/src/utils/tauriCsp.test.ts b/src/utils/tauriCsp.test.ts
index 9b440496..2aefef22 100644
--- a/src/utils/tauriCsp.test.ts
+++ b/src/utils/tauriCsp.test.ts
@@ -1,11 +1,14 @@
 import { readFileSync } from 'node:fs'
+import { RUNTIME_STYLE_NONCE_SOURCE } from '../lib/runtimeStyleNonce'
 
 describe('Tauri Content Security Policy', () => {
-  it('keeps broad inline styles available when runtime libraries inject style tags', () => {
+  it('allows nonce-tagged runtime style elements and React style attributes', () => {
     const config = JSON.parse(readFileSync(`${process.cwd()}/src-tauri/tauri.conf.json`, 'utf8'))
-    const styleSrc = config.app.security.csp['style-src'] as string
+    const csp = config.app.security.csp as Record<string, string>
 
-    expect(styleSrc).toContain("'unsafe-inline'")
-    expect(styleSrc).not.toMatch(/'nonce-|sha(256|384|512)-/)
+    expect(csp['style-src']).toContain("'unsafe-inline'")
+    expect(csp['style-src-elem']).toContain(RUNTIME_STYLE_NONCE_SOURCE)
+    expect(csp['style-src-elem']).toContain('https://fonts.googleapis.com')
+    expect(csp['style-src-attr']).toBe("'unsafe-inline'")
   })
 })
diff --git a/tests/smoke/keyboard-command-routing.spec.ts b/tests/smoke/keyboard-command-routing.spec.ts
index 49a8677f..b61cfb5d 100644
--- a/tests/smoke/keyboard-command-routing.spec.ts
+++ b/tests/smoke/keyboard-command-routing.spec.ts
@@ -1,5 +1,6 @@
 import { test, expect, type Page } from '@playwright/test'
 import { APP_COMMAND_IDS } from '../../src/hooks/appCommandCatalog'
+import { RUNTIME_STYLE_NONCE } from '../../src/lib/runtimeStyleNonce'
 import {
   dispatchShortcutEvent,
   triggerMenuCommand,
@@ -19,6 +20,33 @@ async function openAlphaProjectInEditor(page: Page) {
   await page.locator('.bn-editor').click()
 }
 
+function collectRuntimeStyleCspSignals(page: Page): string[] {
+  const messages: string[] = []
+
+  page.on('pageerror', (error) => {
+    messages.push(error.message)
+  })
+
+  page.on('console', (message) => {
+    const text = message.text()
+    if (
+      /Content Security Policy|Refused to apply a stylesheet|Failed to insert placeholder CSS rule|style-src|insertRule/i
+        .test(text)
+    ) {
+      messages.push(text)
+    }
+  })
+
+  return messages
+}
+
+async function expectRuntimeStyleNonce(page: Page): Promise<void> {
+  await expect.poll(async () => page.evaluate((nonce) => {
+    const styles = Array.from(document.querySelectorAll('style')) as HTMLStyleElement[]
+    return styles.some((style) => style.nonce === nonce)
+  }, RUNTIME_STYLE_NONCE), { timeout: 5_000 }).toBe(true)
+}
+
 async function expectPropertiesPanelToggle(page: Page, toggle: () => Promise<void>) {
   const propertiesButton = page.getByRole('button', { name: 'Open the properties panel' })
   await expect(propertiesButton).toBeVisible({ timeout: 5_000 })
@@ -40,14 +68,14 @@ test.describe('keyboard command routing', () => {
   })
 
   test('desktop menu-command bridge creates a note through the shared command path @smoke', async ({ page }) => {
-    const errors: string[] = []
-    page.on('pageerror', (error) => errors.push(error.message))
+    const runtimeStyleCspSignals = collectRuntimeStyleCspSignals(page)
 
     await openFixtureVaultDesktopHarness(page, tempVaultDir)
     await triggerMenuCommand(page, APP_COMMAND_IDS.fileNewNote)
 
     await expect(page.getByTestId('breadcrumb-filename-trigger')).toContainText(/untitled-note-\d+/i, { timeout: 5_000 })
-    expect(errors).toEqual([])
+    await expectRuntimeStyleNonce(page)
+    expect(runtimeStyleCspSignals).toEqual([])
   })
 
   test('desktop menu-command bridge toggles the properties panel through the shared command path @smoke', async ({ page }) => {
@@ -110,14 +138,18 @@ test.describe('keyboard command routing', () => {
   })
 
   test('renderer shortcut bridge toggles the raw editor through the shared keyboard handler @smoke', async ({ page }) => {
+    const runtimeStyleCspSignals = collectRuntimeStyleCspSignals(page)
+
     await openAlphaProjectInEditor(page)
 
     await triggerShortcutCommand(page, APP_COMMAND_IDS.editToggleRawEditor)
     await expect(page.getByTestId('raw-editor-codemirror')).toBeVisible({ timeout: 5_000 })
+    await expectRuntimeStyleNonce(page)
 
     await triggerShortcutCommand(page, APP_COMMAND_IDS.editToggleRawEditor)
     await expect(page.getByTestId('raw-editor-codemirror')).not.toBeVisible({ timeout: 5_000 })
     await expect(page.locator('.bn-editor')).toBeVisible({ timeout: 5_000 })
+    expect(runtimeStyleCspSignals).toEqual([])
   })
 
   test('desktop menu-command bridge toggles the AI panel, while the wrong modifier event does not @smoke', async ({ page }) => {