diff --git a/apps/web/src/components/settings/account-settings-form.test.tsx b/apps/web/src/components/settings/account-settings-form.test.tsx
new file mode 100644
index 0000000..9273c70
--- /dev/null
+++ b/apps/web/src/components/settings/account-settings-form.test.tsx
@@ -0,0 +1,221 @@
+import { cleanup, fireEvent, render, screen, waitFor } from '@testing-library/react';
+import { afterEach, describe, expect, it, vi } from 'vitest';
+import { AccountSettingsForm } from './account-settings-form';
+
+/**
+ * account-settings-form.test — Akzentfarbe Hex-Eingabe (quick-260917-gsh).
+ * next-intl-Mock de.json-gestuetzt (Muster: desktop-app-settings.test.tsx),
+ * `@/lib/auth-actions` per vi.hoisted + vi.mock ersetzt.
+ */
+vi.mock('next-intl', async () => {
+  const messages = (await import('@/messages/de.json')).default as Record<string, unknown>;
+  const lookup = (path: string): string | undefined =>
+    path.split('.').reduce<unknown>((o, k) => (o && typeof o === 'object' ? (o as any)[k] : undefined), messages) as
+      | string
+      | undefined;
+  return {
+    useTranslations:
+      (ns?: string) =>
+      (key: string, values?: Record<string, unknown>) => {
+        const raw = lookup(ns ? `${ns}.${key}` : key) ?? key;
+        return values ? raw.replace(/\{(\w+)\}/g, (_: string, n: string) => String(values[n] ?? '')) : raw;
+      },
+    useLocale: () => 'de',
+  };
+});
+
+const { fetchCurrentUser, updateAccentColorAction, changePasswordAction, uploadAvatarAction, deleteAvatarAction } =
+  vi.hoisted(() => ({
+    fetchCurrentUser: vi.fn(),
+    updateAccentColorAction: vi.fn(),
+    changePasswordAction: vi.fn(),
+    uploadAvatarAction: vi.fn(),
+    deleteAvatarAction: vi.fn(),
+  }));
+
+vi.mock('@/lib/auth-actions', () => ({
+  fetchCurrentUser,
+  updateAccentColorAction,
+  changePasswordAction,
+  uploadAvatarAction,
+  deleteAvatarAction,
+}));
+
+afterEach(() => {
+  cleanup();
+  vi.clearAllMocks();
+});
+
+describe('AccountSettingsForm — Akzentfarbe Hex-Eingabe', () => {
+  it('prefills the hex textfield and the color picker from the loaded user', async () => {
+    fetchCurrentUser.mockResolvedValue({
+      id: 'u1',
+      username: 'max',
+      displayName: 'Max',
+      role: 'USER',
+      tenantId: 't1',
+      isLocalUser: true,
+      hasAvatar: false,
+      accentColor: '#123456',
+    });
+
+    render(<AccountSettingsForm />);
+
+    const hexInput = (await screen.findByRole('textbox', {
+      name: 'Hex-Code',
+    })) as HTMLInputElement;
+    expect(hexInput.value).toBe('#123456');
+
+    const colorPicker = document.querySelector('input[type="color"]') as HTMLInputElement;
+    expect(colorPicker.value).toBe('#123456');
+  });
+
+  it('accepts a valid hex value typed without # and syncs the color picker', async () => {
+    fetchCurrentUser.mockResolvedValue({
+      id: 'u1',
+      username: 'max',
+      displayName: 'Max',
+      role: 'USER',
+      tenantId: 't1',
+      isLocalUser: true,
+      hasAvatar: false,
+      accentColor: '#123456',
+    });
+
+    render(<AccountSettingsForm />);
+    const hexInput = (await screen.findByRole('textbox', {
+      name: 'Hex-Code',
+    })) as HTMLInputElement;
+    const colorPicker = document.querySelector('input[type="color"]') as HTMLInputElement;
+
+    fireEvent.change(hexInput, { target: { value: 'FFED00' } });
+
+    expect(colorPicker.value).toBe('#ffed00');
+    expect(hexInput).toHaveAttribute('aria-invalid', 'false');
+    expect(screen.getByText('Farbe speichern')).not.toBeDisabled();
+  });
+
+  it('marks an invalid hex value, blocks save, and keeps the last valid color picker value', async () => {
+    fetchCurrentUser.mockResolvedValue({
+      id: 'u1',
+      username: 'max',
+      displayName: 'Max',
+      role: 'USER',
+      tenantId: 't1',
+      isLocalUser: true,
+      hasAvatar: false,
+      accentColor: '#123456',
+    });
+
+    render(<AccountSettingsForm />);
+    const hexInput = (await screen.findByRole('textbox', {
+      name: 'Hex-Code',
+    })) as HTMLInputElement;
+    const colorPicker = document.querySelector('input[type="color"]') as HTMLInputElement;
+
+    fireEvent.change(hexInput, { target: { value: '#ggg' } });
+
+    expect(hexInput).toHaveAttribute('aria-invalid', 'true');
+    expect(hexInput.className).toContain('border-destructive');
+    expect(
+      screen.getByText('Ungültiger Farbwert. Bitte geben Sie sechs Hexadezimalzeichen ein, z. B. #ffed00.'),
+    ).toBeInTheDocument();
+    expect(screen.getByText('Farbe speichern')).toBeDisabled();
+    expect(colorPicker.value).toBe('#123456');
+  });
+
+  it('syncs the hex textfield when the color picker changes', async () => {
+    fetchCurrentUser.mockResolvedValue({
+      id: 'u1',
+      username: 'max',
+      displayName: 'Max',
+      role: 'USER',
+      tenantId: 't1',
+      isLocalUser: true,
+      hasAvatar: false,
+      accentColor: '#123456',
+    });
+
+    render(<AccountSettingsForm />);
+    await screen.findByRole('textbox', { name: 'Hex-Code' });
+    const hexInput = screen.getByRole('textbox', { name: 'Hex-Code' }) as HTMLInputElement;
+    const colorPicker = document.querySelector('input[type="color"]') as HTMLInputElement;
+
+    fireEvent.change(colorPicker, { target: { value: '#00ff00' } });
+
+    expect(hexInput.value).toBe('#00ff00');
+  });
+
+  it('normalizes the hex textfield to canonical form on blur', async () => {
+    fetchCurrentUser.mockResolvedValue({
+      id: 'u1',
+      username: 'max',
+      displayName: 'Max',
+      role: 'USER',
+      tenantId: 't1',
+      isLocalUser: true,
+      hasAvatar: false,
+      accentColor: '#123456',
+    });
+
+    render(<AccountSettingsForm />);
+    const hexInput = (await screen.findByRole('textbox', {
+      name: 'Hex-Code',
+    })) as HTMLInputElement;
+
+    fireEvent.change(hexInput, { target: { value: '#fe0' } });
+    fireEvent.blur(hexInput);
+
+    expect(hexInput.value).toBe('#ffee00');
+  });
+
+  it('resets both the hex textfield and the color picker on "Zurücksetzen"', async () => {
+    fetchCurrentUser.mockResolvedValue({
+      id: 'u1',
+      username: 'max',
+      displayName: 'Max',
+      role: 'USER',
+      tenantId: 't1',
+      isLocalUser: true,
+      hasAvatar: false,
+      accentColor: '#123456',
+    });
+    updateAccentColorAction.mockResolvedValue({ success: true });
+
+    render(<AccountSettingsForm />);
+    const hexInput = (await screen.findByRole('textbox', {
+      name: 'Hex-Code',
+    })) as HTMLInputElement;
+    const colorPicker = document.querySelector('input[type="color"]') as HTMLInputElement;
+
+    fireEvent.click(screen.getByText('Zurücksetzen'));
+
+    await waitFor(() => {
+      expect(hexInput.value).toBe('#ffed00');
+    });
+    expect(colorPicker.value).toBe('#ffed00');
+    expect(updateAccentColorAction).toHaveBeenCalledWith(null);
+  });
+
+  it('saves the normalized color and shows the success message', async () => {
+    fetchCurrentUser.mockResolvedValue({
+      id: 'u1',
+      username: 'max',
+      displayName: 'Max',
+      role: 'USER',
+      tenantId: 't1',
+      isLocalUser: true,
+      hasAvatar: false,
+      accentColor: '#ffed00',
+    });
+    updateAccentColorAction.mockResolvedValue({ success: true });
+
+    render(<AccountSettingsForm />);
+    await screen.findByRole('textbox', { name: 'Hex-Code' });
+
+    fireEvent.click(screen.getByText('Farbe speichern'));
+
+    expect(await screen.findByText('Akzentfarbe erfolgreich gespeichert.')).toBeInTheDocument();
+    expect(updateAccentColorAction).toHaveBeenCalledWith('#ffed00');
+  });
+});
diff --git a/apps/web/src/components/settings/account-settings-form.tsx b/apps/web/src/components/settings/account-settings-form.tsx
index d026943..eba691d 100644
--- a/apps/web/src/components/settings/account-settings-form.tsx
+++ b/apps/web/src/components/settings/account-settings-form.tsx
@@ -11,6 +11,7 @@ import {
 } from '@/lib/auth-actions';
 import { useAuthStore } from '@/lib/stores/auth-store';
 import { BRAND_YELLOW } from '@/components/brand/brand';
+import { normalizeHexColor } from '@/lib/color';
 
 const DEFAULT_ACCENT = BRAND_YELLOW;
 
@@ -38,6 +39,8 @@ export function AccountSettingsForm() {
 
   // Accent color state
   const [accentColor, setAccentColor] = useState<string>(DEFAULT_ACCENT);
+  const [hexInput, setHexInput] = useState<string>(DEFAULT_ACCENT);
+  const isHexValid = normalizeHexColor(hexInput) !== null;
   const [accentSuccess, setAccentSuccess] = useState(false);
   const [accentError, setAccentError] = useState<string | null>(null);
   const [isAccentPending, startAccentTransition] = useTransition();
@@ -48,7 +51,9 @@ export function AccountSettingsForm() {
         setIsLocalUser(u.isLocalUser ?? false);
         setUsername(u.displayName ?? u.username ?? '');
         setHasAvatar(!!u.hasAvatar);
-        setAccentColor(u.accentColor ?? DEFAULT_ACCENT);
+        const c = u.accentColor ?? DEFAULT_ACCENT;
+        setAccentColor(c);
+        setHexInput(c);
       }
     });
   }, []);
@@ -113,6 +118,7 @@ export function AccountSettingsForm() {
   }
 
   function handleSaveAccentColor() {
+    if (!isHexValid) return;
     setAccentSuccess(false);
     setAccentError(null);
     startAccentTransition(async () => {
@@ -128,6 +134,7 @@ export function AccountSettingsForm() {
 
   function handleResetAccentColor() {
     setAccentColor(DEFAULT_ACCENT);
+    setHexInput(DEFAULT_ACCENT);
     setAccentSuccess(false);
     setAccentError(null);
     startAccentTransition(async () => {
@@ -212,14 +219,41 @@ export function AccountSettingsForm() {
           {t('account.accentColorLabel')}
         </h2>
         <p className="text-xs text-muted-foreground mb-4">{t('account.accentColorHelp')}</p>
-        <div className="flex items-center gap-3 mb-4">
+        <div className="flex items-center gap-3 mb-1">
           <input
             type="color"
             value={accentColor}
-            onChange={(e) => setAccentColor(e.target.value)}
+            onChange={(e) => {
+              setAccentColor(e.target.value);
+              setHexInput(e.target.value);
+            }}
             className="h-10 w-16 cursor-pointer rounded-md border border-input p-1"
           />
-          <span className="font-mono text-sm text-muted-foreground">{accentColor}</span>
+          <input
+            id="accentColorHex"
+            type="text"
+            inputMode="text"
+            autoComplete="off"
+            spellCheck={false}
+            maxLength={7}
+            placeholder={DEFAULT_ACCENT}
+            value={hexInput}
+            aria-label={t('account.accentColorHex')}
+            aria-invalid={!isHexValid}
+            onChange={(e) => {
+              const raw = e.target.value;
+              setHexInput(raw);
+              const n = normalizeHexColor(raw);
+              if (n) setAccentColor(n);
+            }}
+            onBlur={() => {
+              const n = normalizeHexColor(hexInput);
+              if (n) setHexInput(n);
+            }}
+            className={`h-10 w-28 rounded-md border bg-background px-3 py-2 font-mono text-sm focus-visible:outline-none focus-visible:ring-2 focus-visible:ring-ring ${
+              isHexValid ? 'border-input' : 'border-destructive'
+            }`}
+          />
           <button
             type="button"
             onClick={handleResetAccentColor}
@@ -229,6 +263,9 @@ export function AccountSettingsForm() {
             {t('account.accentColorReset')}
           </button>
         </div>
+        {!isHexValid && (
+          <p className="text-xs text-destructive mb-3">{t('account.accentColorHexInvalid')}</p>
+        )}
         {accentSuccess && (
           <div className="rounded-md bg-green-50 dark:bg-green-900/20 border border-green-200 dark:border-green-800 px-4 py-3 text-sm text-green-800 dark:text-green-200 mb-3">
             {t('account.accentColorSuccess')}
@@ -242,7 +279,7 @@ export function AccountSettingsForm() {
         <button
           type="button"
           onClick={handleSaveAccentColor}
-          disabled={isAccentPending}
+          disabled={isAccentPending || !isHexValid}
           className="inline-flex items-center justify-center rounded-md bg-primary px-4 py-2 text-sm font-medium text-primary-foreground hover:opacity-90 transition-opacity disabled:opacity-50"
         >
           {isAccentPending ? '...' : t('account.accentColorSave')}
diff --git a/apps/web/src/lib/color.test.ts b/apps/web/src/lib/color.test.ts
new file mode 100644
index 0000000..e900fdf
--- /dev/null
+++ b/apps/web/src/lib/color.test.ts
@@ -0,0 +1,44 @@
+import { describe, expect, it } from 'vitest';
+import { normalizeHexColor } from './color';
+
+/**
+ * color.test — Normalisierung der Hex-Eingabe der Akzentfarbe
+ * (quick-260917-gsh).
+ */
+describe('normalizeHexColor', () => {
+  it('accepts a canonical six-digit hex value with leading #', () => {
+    expect(normalizeHexColor('#ffed00')).toBe('#ffed00');
+  });
+
+  it('accepts a six-digit value without # and uppercase letters', () => {
+    expect(normalizeHexColor('FFED00')).toBe('#ffed00');
+  });
+
+  it('expands a three-digit shorthand', () => {
+    expect(normalizeHexColor('#fe0')).toBe('#ffee00');
+  });
+
+  it('trims surrounding whitespace and lowercases mixed case', () => {
+    expect(normalizeHexColor('  #FfEd00 ')).toBe('#ffed00');
+  });
+
+  it('rejects non-hex characters', () => {
+    expect(normalizeHexColor('#ggg')).toBeNull();
+  });
+
+  it('rejects the wrong digit count (5)', () => {
+    expect(normalizeHexColor('#12345')).toBeNull();
+  });
+
+  it('rejects an empty string', () => {
+    expect(normalizeHexColor('')).toBeNull();
+  });
+
+  it('rejects a lone hash', () => {
+    expect(normalizeHexColor('#')).toBeNull();
+  });
+
+  it('rejects the wrong digit count (7)', () => {
+    expect(normalizeHexColor('#1234567')).toBeNull();
+  });
+});
diff --git a/apps/web/src/lib/color.ts b/apps/web/src/lib/color.ts
new file mode 100644
index 0000000..9e0d65c
--- /dev/null
+++ b/apps/web/src/lib/color.ts
@@ -0,0 +1,30 @@
+/**
+ * Normalisierung der Hex-Eingabe der persoenlichen Akzentfarbe
+ * (Einstellungen → Konto, quick-260917-gsh).
+ *
+ * `PATCH /users/me/accent-color` verlangt serverseitig `/^#[0-9a-fA-F]{6}$/` —
+ * diese Funktion bringt Roheingaben (mit/ohne `#`, Kurzform, Gross-/
+ * Kleinschreibung, umgebender Leerraum) in genau diese kanonische Form
+ * oder liefert `null`, wenn das nicht moeglich ist.
+ */
+
+const HEX_PATTERN = /^[0-9a-f]{3}$|^[0-9a-f]{6}$/i;
+
+export function normalizeHexColor(input: string): string | null {
+  const trimmed = input.trim();
+  const withoutHash = trimmed.startsWith('#') ? trimmed.slice(1) : trimmed;
+
+  if (!HEX_PATTERN.test(withoutHash)) {
+    return null;
+  }
+
+  const expanded =
+    withoutHash.length === 3
+      ? withoutHash
+          .split('')
+          .map((ch) => ch + ch)
+          .join('')
+      : withoutHash;
+
+  return `#${expanded.toLowerCase()}`;
+}
diff --git a/apps/web/src/messages/de.json b/apps/web/src/messages/de.json
index 18b6f9d..5f8ea4a 100644
--- a/apps/web/src/messages/de.json
+++ b/apps/web/src/messages/de.json
@@ -149,6 +149,8 @@
       "accentColorSave": "Farbe speichern",
       "accentColorSuccess": "Akzentfarbe erfolgreich gespeichert.",
       "accentColorError": "Speichern fehlgeschlagen.",
+      "accentColorHex": "Hex-Code",
+      "accentColorHexInvalid": "Ungültiger Farbwert. Bitte geben Sie sechs Hexadezimalzeichen ein, z. B. #ffed00.",
       "deleteAvatarCta": "Bild löschen",
       "deleteAvatarSuccess": "Profilbild erfolgreich gelöscht.",
       "deleteAvatarError": "Löschen fehlgeschlagen."
diff --git a/apps/web/src/messages/en.json b/apps/web/src/messages/en.json
index 0031532..33ded69 100644
--- a/apps/web/src/messages/en.json
+++ b/apps/web/src/messages/en.json
@@ -149,6 +149,8 @@
       "accentColorSave": "Save color",
       "accentColorSuccess": "Accent color saved successfully.",
       "accentColorError": "Failed to save color.",
+      "accentColorHex": "Hex code",
+      "accentColorHexInvalid": "Invalid color value. Please enter six hexadecimal characters, e.g. #ffed00.",
       "deleteAvatarCta": "Delete picture",
       "deleteAvatarSuccess": "Profile picture deleted successfully.",
       "deleteAvatarError": "Failed to delete picture."