diff --git a/src/app/dashboard/adressbuch/page.tsx b/src/app/dashboard/adressbuch/page.tsx
index 3b79a5d..56998a7 100644
--- a/src/app/dashboard/adressbuch/page.tsx
+++ b/src/app/dashboard/adressbuch/page.tsx
@@ -124,7 +124,7 @@ export default async function AdressbuchPage() {
       <div className="flex flex-col gap-1">
         <h1 className="text-2xl font-bold tracking-tight">Adressbuch</h1>
         <p className="max-w-2xl text-sm text-muted-foreground">
-          Haushalte und Kontaktdaten, die explizit fuer das interne
+          Haushalte und Kontaktdaten, die explizit für das interne
           Kita-Adressbuch freigegeben wurden.
         </p>
       </div>
diff --git a/src/app/dashboard/profil/actions.ts b/src/app/dashboard/profil/actions.ts
index 42aad51..31e2dda 100644
--- a/src/app/dashboard/profil/actions.ts
+++ b/src/app/dashboard/profil/actions.ts
@@ -6,20 +6,76 @@ import { z } from "zod";
 import { requireKitaSession } from "@/lib/auth-utils";
 import { prisma } from "@/lib/prisma";
 
-const childSchema = z.object({
-  firstName: z.string().min(1, "Vorname ist erforderlich.").max(100).trim(),
-  lastName: z.string().min(1, "Nachname ist erforderlich.").max(100).trim(),
-  dateOfBirth: z.string().optional(),
-});
+// Telefonnummern: führendes "+" optional, dann Ziffern, Leerzeichen, Bindestriche,
+// Klammern oder Schrägstriche. Mindestens 6 Ziffern damit es plausibel ist.
+// Schließt damit "abc-123-not-a-phone" aus, lässt aber internationale Formate zu.
+const phonePattern = /^[+]?[0-9][\d\s\-()/.]{4,}$/;
+
+// PLZ: Ziffern/Buchstaben/Leerzeichen/Bindestriche, 3–10 Zeichen.
+// Kein striktes DE-Format (5 Ziffern), damit auch AT/CH/UK denkbar sind.
+const postalCodePattern = /^[0-9A-Za-z][0-9A-Za-z\s-]{2,9}$/;
+
+const childSchema = z
+  .object({
+    firstName: z.string().min(1, "Vorname ist erforderlich.").max(100).trim(),
+    lastName: z.string().min(1, "Nachname ist erforderlich.").max(100).trim(),
+    dateOfBirth: z.string().optional(),
+  })
+  .superRefine((data, ctx) => {
+    if (!data.dateOfBirth) return;
+    const parsed = new Date(`${data.dateOfBirth}T00:00:00`);
+    if (Number.isNaN(parsed.getTime())) {
+      ctx.addIssue({
+        path: ["dateOfBirth"],
+        code: "custom",
+        message: "Bitte ein gültiges Datum angeben.",
+      });
+      return;
+    }
+    // In der Zukunft geborene Kinder existieren nicht.
+    const today = new Date();
+    today.setHours(23, 59, 59, 999);
+    if (parsed > today) {
+      ctx.addIssue({
+        path: ["dateOfBirth"],
+        code: "custom",
+        message: "Geburtsdatum darf nicht in der Zukunft liegen.",
+      });
+    }
+    // Schutz vor offensichtlichen Tippfehlern (1899 statt 1989 o.ä.).
+    if (parsed.getFullYear() < 1900) {
+      ctx.addIssue({
+        path: ["dateOfBirth"],
+        code: "custom",
+        message: "Bitte ein realistisches Geburtsdatum angeben.",
+      });
+    }
+  });
 
 const familySchema = z.object({
   familyName: z.string().min(1, "Familienname ist erforderlich.").max(120).trim(),
 });
 
 const contactSchema = z.object({
-  phone: z.string().trim().max(50).optional(),
+  phone: z
+    .string()
+    .trim()
+    .max(50)
+    .optional()
+    .refine(
+      (v) => !v || phonePattern.test(v),
+      "Bitte eine gültige Telefonnummer angeben.",
+    ),
   street: z.string().trim().max(120).optional(),
-  postalCode: z.string().trim().max(20).optional(),
+  postalCode: z
+    .string()
+    .trim()
+    .max(20)
+    .optional()
+    .refine(
+      (v) => !v || postalCodePattern.test(v),
+      "Bitte eine gültige Postleitzahl angeben.",
+    ),
   city: z.string().trim().max(100).optional(),
 });
 
@@ -30,6 +86,16 @@ function parseDateInput(value?: string) {
   return Number.isNaN(date.getTime()) ? null : date;
 }
 
+// Gibt die erste konkrete Field-Error-Message aus einem Zod-Fehler zurück,
+// damit der User nicht nur "Ungültige Eingabedaten" sieht.
+function firstZodMessage(
+  error: z.ZodError,
+  fallback: string,
+): string {
+  const issue = error.issues[0];
+  return issue?.message || fallback;
+}
+
 async function requireOwnFamilyChild(
   childId: string,
   familyId: string | null,
@@ -51,7 +117,7 @@ export async function createMyChild(rawPayload: unknown) {
   }
 
   if (!parsed.success) {
-    return { error: "Ungültige Eingabedaten." };
+    return { error: firstZodMessage(parsed.error, "Ungültige Eingabedaten.") };
   }
 
   try {
@@ -117,7 +183,7 @@ export async function updateMyContact(rawPayload: unknown) {
   const parsed = contactSchema.safeParse(rawPayload);
 
   if (!parsed.success) {
-    return { error: "Ungültige Kontaktdaten." };
+    return { error: firstZodMessage(parsed.error, "Ungültige Kontaktdaten.") };
   }
 
   try {
@@ -146,7 +212,7 @@ export async function updateMyChild(childId: string, rawPayload: unknown) {
   const parsed = childSchema.safeParse(rawPayload);
 
   if (!parsed.success) {
-    return { error: "Ungültige Eingabedaten." };
+    return { error: firstZodMessage(parsed.error, "Ungültige Eingabedaten.") };
   }
 
   try {
diff --git a/src/app/invite/[token]/actions.ts b/src/app/invite/[token]/actions.ts
index 0eed9aa..07cf879 100644
--- a/src/app/invite/[token]/actions.ts
+++ b/src/app/invite/[token]/actions.ts
@@ -34,6 +34,16 @@ const inviteSchema = z
 const PRIVACY_POLICY_VERSION = "2026-05-01";
 
 export type InviteState = {
+  // Bumped per call so the client can key uncontrolled inputs and force a
+  // remount after a failed submit (React's <form action> wipes them
+  // otherwise).
+  attempt: number;
+  // Echoed checkbox states so failed submits don't lose the user's consent
+  // ticks. Passwords are NEVER echoed back from the server.
+  values?: {
+    acceptPrivacyPolicy?: boolean;
+    directoryOptIn?: boolean;
+  };
   errors?: {
     password?: string[];
     confirmPassword?: string[];
@@ -43,10 +53,22 @@ export type InviteState = {
   };
 };
 
+export const initialInviteState: InviteState = { attempt: 0 };
+
+function echoCheckboxValues(formData: FormData): InviteState["values"] {
+  return {
+    acceptPrivacyPolicy: formData.get("acceptPrivacyPolicy") === "on",
+    directoryOptIn: formData.get("directoryOptIn") === "on",
+  };
+}
+
 export async function acceptInviteAction(
-  _prev: InviteState,
+  prev: InviteState,
   formData: FormData,
 ): Promise<InviteState> {
+  const attempt = prev.attempt + 1;
+  const values = echoCheckboxValues(formData);
+
   const parsed = inviteSchema.safeParse({
     token: formData.get("token"),
     password: formData.get("password"),
@@ -56,7 +78,7 @@ export async function acceptInviteAction(
   });
 
   if (!parsed.success) {
-    return { errors: parsed.error.flatten().fieldErrors };
+    return { attempt, values, errors: parsed.error.flatten().fieldErrors };
   }
 
   const { token, password, directoryOptIn } = parsed.data;
@@ -68,10 +90,16 @@ export async function acceptInviteAction(
   });
 
   if (!verificationToken) {
-    return { errors: { _form: ["Einladungslink ist ungültig."] } };
+    return {
+      attempt,
+      values,
+      errors: { _form: ["Einladungslink ist ungültig."] },
+    };
   }
   if (verificationToken.expires < now) {
     return {
+      attempt,
+      values,
       errors: {
         _form: [
           "Dieser Einladungslink ist abgelaufen. Bitte wende dich an deinen Administrator.",
@@ -89,11 +117,17 @@ export async function acceptInviteAction(
   });
 
   if (!user) {
-    return { errors: { _form: ["Benutzer nicht gefunden."] } };
+    return {
+      attempt,
+      values,
+      errors: { _form: ["Benutzer nicht gefunden."] },
+    };
   }
   if (user.passwordHash !== "") {
     // Invite wurde bereits eingelöst
     return {
+      attempt,
+      values,
       errors: {
         _form: [
           "Dieser Einladungslink wurde bereits verwendet. Bitte melde dich an.",
@@ -131,5 +165,5 @@ export async function acceptInviteAction(
   });
 
   // Unreachable – signIn redirected.
-  return {};
+  return { attempt };
 }
diff --git a/src/app/invite/[token]/invite-form.tsx b/src/app/invite/[token]/invite-form.tsx
index b115cc5..d27b6bc 100644
--- a/src/app/invite/[token]/invite-form.tsx
+++ b/src/app/invite/[token]/invite-form.tsx
@@ -6,9 +6,7 @@ import { Button } from "@/components/ui/button";
 import { Input } from "@/components/ui/input";
 import { Label } from "@/components/ui/label";
 import { Checkbox } from "@/components/ui/checkbox";
-import { acceptInviteAction, type InviteState } from "./actions";
-
-const initialState: InviteState = {};
+import { acceptInviteAction, initialInviteState } from "./actions";
 
 // =====================================================================
 // InviteForm · Client Component
@@ -27,9 +25,14 @@ export function InviteForm({
 }) {
   const [state, formAction, pending] = useActionState(
     acceptInviteAction,
-    initialState,
+    initialInviteState,
   );
 
+  // Bumping the key on each attempt forces uncontrolled inputs (including
+  // checkboxes) to remount with the echoed defaultChecked values after a
+  // failed submit. Passwords stay empty for security.
+  const attemptKey = state.attempt;
+
   return (
     <form action={formAction} className="space-y-5">
       {/* Token als verstecktes Feld */}
@@ -45,17 +48,30 @@ export function InviteForm({
       <div className="space-y-1.5">
         <Label htmlFor="password">Passwort wählen</Label>
         <Input
+          key={`password-${attemptKey}`}
           id="password"
           name="password"
           type="password"
           autoComplete="new-password"
           required
           aria-invalid={!!state.errors?.password}
+          aria-describedby={
+            state.errors?.password ? "password-error" : "password-helper"
+          }
         />
         {state.errors?.password?.[0] ? (
-          <p className="text-xs text-destructive">{state.errors.password[0]}</p>
+          <p
+            id="password-error"
+            role="alert"
+            aria-live="polite"
+            className="text-xs text-destructive"
+          >
+            {state.errors.password[0]}
+          </p>
         ) : (
-          <p className="text-xs text-muted-foreground">Mindestens 8 Zeichen.</p>
+          <p id="password-helper" className="text-xs text-muted-foreground">
+            Mindestens 8 Zeichen.
+          </p>
         )}
       </div>
 
@@ -63,15 +79,26 @@ export function InviteForm({
       <div className="space-y-1.5">
         <Label htmlFor="confirmPassword">Passwort bestätigen</Label>
         <Input
+          key={`confirmPassword-${attemptKey}`}
           id="confirmPassword"
           name="confirmPassword"
           type="password"
           autoComplete="new-password"
           required
           aria-invalid={!!state.errors?.confirmPassword}
+          aria-describedby={
+            state.errors?.confirmPassword
+              ? "confirmPassword-error"
+              : undefined
+          }
         />
         {state.errors?.confirmPassword?.[0] && (
-          <p className="text-xs text-destructive">
+          <p
+            id="confirmPassword-error"
+            role="alert"
+            aria-live="polite"
+            className="text-xs text-destructive"
+          >
             {state.errors.confirmPassword[0]}
           </p>
         )}
@@ -85,10 +112,17 @@ export function InviteForm({
 
         <div className="flex items-start gap-3">
           <Checkbox
+            key={`acceptPrivacyPolicy-${attemptKey}`}
             id="acceptPrivacyPolicy"
             name="acceptPrivacyPolicy"
             required
+            defaultChecked={state.values?.acceptPrivacyPolicy === true}
             aria-invalid={!!state.errors?.acceptPrivacyPolicy}
+            aria-describedby={
+              state.errors?.acceptPrivacyPolicy
+                ? "acceptPrivacyPolicy-error"
+                : undefined
+            }
           />
           <div className="space-y-0.5">
             <Label htmlFor="acceptPrivacyPolicy" className="text-sm font-normal">
@@ -104,7 +138,12 @@ export function InviteForm({
               gelesen und akzeptiere sie. <span className="text-destructive">*</span>
             </Label>
             {state.errors?.acceptPrivacyPolicy?.[0] && (
-              <p className="text-xs text-destructive">
+              <p
+                id="acceptPrivacyPolicy-error"
+                role="alert"
+                aria-live="polite"
+                className="text-xs text-destructive"
+              >
                 {state.errors.acceptPrivacyPolicy[0]}
               </p>
             )}
@@ -113,8 +152,10 @@ export function InviteForm({
 
         <div className="flex items-start gap-3">
           <Checkbox
+            key={`directoryOptIn-${attemptKey}`}
             id="directoryOptIn"
             name="directoryOptIn"
+            defaultChecked={state.values?.directoryOptIn === true}
             aria-invalid={!!state.errors?.directoryOptIn}
           />
           <div className="space-y-0.5">
@@ -128,7 +169,11 @@ export function InviteForm({
 
       {/* Globaler Fehler */}
       {state.errors?._form?.[0] && (
-        <p className="rounded-md border border-destructive/50 bg-destructive/10 p-3 text-sm text-destructive">
+        <p
+          role="alert"
+          aria-live="polite"
+          className="rounded-md border border-destructive/50 bg-destructive/10 p-3 text-sm text-destructive"
+        >
           {state.errors._form[0]}
         </p>
       )}
diff --git a/src/emails/AlertEmail.tsx b/src/emails/AlertEmail.tsx
index 69aa99f..6b0c3c1 100644
--- a/src/emails/AlertEmail.tsx
+++ b/src/emails/AlertEmail.tsx
@@ -11,6 +11,8 @@ import {
   Text,
 } from "@react-email/components";
 
+import { fontStack } from "./_styles";
+
 type AlertEmailProps = {
   date: string;
   childName: string;
@@ -25,26 +27,26 @@ export function AlertEmail({
   return (
     <Html lang="de">
       <Head />
-      <Preview>Dringender Notdienst-Alarm fuer {date}</Preview>
+      <Preview>Dringender Notdienst-Alarm für {date}</Preview>
       <Body style={styles.body}>
         <Container style={styles.container}>
           <Section style={styles.alertBar}>
             <Text style={styles.kicker}>Dringend</Text>
-            <Heading style={styles.heading}>Notdienst heute bestaetigen</Heading>
+            <Heading style={styles.heading}>Notdienst heute bestätigen</Heading>
             <Text style={styles.lead}>
-              Eine Fachkraft ist ausgefallen. Fuer {childName} ist ein
+              Eine Fachkraft ist ausgefallen. Für {childName} ist ein
               Notdienst-Einsatz am {date} hinterlegt.
             </Text>
           </Section>
 
           <Section style={styles.card}>
             <Text style={styles.text}>
-              Bitte bestaetige schnell, ob du den Notdienst uebernehmen kannst,
-              damit die Kita den Tag verlaesslich planen kann.
+              Bitte bestätige schnell, ob du den Notdienst übernehmen kannst,
+              damit die Kita den Tag verlässlich planen kann.
             </Text>
 
             <Button href={confirmLink} style={styles.button}>
-              Notdienst bestaetigen
+              Notdienst bestätigen
             </Button>
 
             <Section style={styles.detailBox}>
@@ -75,8 +77,7 @@ const styles = {
   body: {
     margin: 0,
     backgroundColor: "#fff7ed",
-    fontFamily:
-      '-apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif',
+    fontFamily: fontStack,
     color: "#30170f",
   },
   container: {
@@ -108,12 +109,14 @@ const styles = {
     fontSize: "30px",
     lineHeight: "1.16",
     fontWeight: 850,
+    fontFamily: fontStack,
   },
   lead: {
     margin: 0,
     color: "#ffe4e6",
     fontSize: "16px",
     lineHeight: "1.55",
+    fontFamily: fontStack,
   },
   card: {
     padding: "28px",
@@ -127,6 +130,7 @@ const styles = {
     color: "#44251a",
     fontSize: "16px",
     lineHeight: "1.65",
+    fontFamily: fontStack,
   },
   button: {
     display: "inline-block",
@@ -137,6 +141,7 @@ const styles = {
     fontSize: "15px",
     fontWeight: 800,
     textDecoration: "none",
+    fontFamily: fontStack,
   },
   detailBox: {
     margin: "28px 0 0",
@@ -182,5 +187,6 @@ const styles = {
     fontSize: "12px",
     lineHeight: "1.5",
     textAlign: "center" as const,
+    fontFamily: fontStack,
   },
 };
diff --git a/src/emails/ContactConfirmationEmail.tsx b/src/emails/ContactConfirmationEmail.tsx
index dc22158..7e78434 100644
--- a/src/emails/ContactConfirmationEmail.tsx
+++ b/src/emails/ContactConfirmationEmail.tsx
@@ -13,6 +13,7 @@ import {
   contactRequestTypeLabels,
   type ContactRequestInput,
 } from "@/lib/contact-schema";
+import { fontStack } from "./_styles";
 
 type ContactConfirmationEmailProps = ContactRequestInput;
 
@@ -69,14 +70,14 @@ function InfoRow({ label, value }: { label: string; value: string }) {
 const body = {
   margin: 0,
   backgroundColor: "#f8faf8",
-  fontFamily:
-    '-apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif',
+  fontFamily: fontStack,
 };
 
 const container = {
   margin: "0 auto",
   padding: "32px 24px",
   maxWidth: "620px",
+  fontFamily: fontStack,
 };
 
 const heading = {
@@ -84,6 +85,7 @@ const heading = {
   color: "#0f172a",
   fontSize: "28px",
   lineHeight: "34px",
+  fontFamily: fontStack,
 };
 
 const intro = {
@@ -91,6 +93,7 @@ const intro = {
   color: "#475569",
   fontSize: "15px",
   lineHeight: "24px",
+  fontFamily: fontStack,
 };
 
 const summaryBox = {
@@ -98,6 +101,7 @@ const summaryBox = {
   borderRadius: "10px",
   backgroundColor: "#ffffff",
   padding: "18px",
+  fontFamily: fontStack,
 };
 
 const label = {
@@ -107,6 +111,7 @@ const label = {
   fontWeight: 700,
   letterSpacing: "0.04em",
   textTransform: "uppercase" as const,
+  fontFamily: fontStack,
 };
 
 const row = {
@@ -114,6 +119,7 @@ const row = {
   color: "#0f172a",
   fontSize: "15px",
   lineHeight: "22px",
+  fontFamily: fontStack,
 };
 
 const messageLabel = {
@@ -123,6 +129,7 @@ const messageLabel = {
   fontWeight: 700,
   letterSpacing: "0.04em",
   textTransform: "uppercase" as const,
+  fontFamily: fontStack,
 };
 
 const messageText = {
@@ -131,6 +138,7 @@ const messageText = {
   fontSize: "15px",
   lineHeight: "24px",
   whiteSpace: "pre-wrap" as const,
+  fontFamily: fontStack,
 };
 
 const footer = {
@@ -138,4 +146,5 @@ const footer = {
   color: "#64748b",
   fontSize: "13px",
   lineHeight: "20px",
+  fontFamily: fontStack,
 };
diff --git a/src/emails/ContactRequestEmail.tsx b/src/emails/ContactRequestEmail.tsx
index af5b94a..ae21c90 100644
--- a/src/emails/ContactRequestEmail.tsx
+++ b/src/emails/ContactRequestEmail.tsx
@@ -13,6 +13,7 @@ import {
   contactRequestTypeLabels,
   type ContactRequestInput,
 } from "@/lib/contact-schema";
+import { fontStack } from "./_styles";
 
 type ContactRequestEmailProps = ContactRequestInput;
 
@@ -72,14 +73,14 @@ function InfoRow({ label, value }: { label: string; value: string }) {
 const body = {
   margin: 0,
   backgroundColor: "#f8faf8",
-  fontFamily:
-    '-apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif',
+  fontFamily: fontStack,
 };
 
 const container = {
   margin: "0 auto",
   padding: "32px 24px",
   maxWidth: "620px",
+  fontFamily: fontStack,
 };
 
 const heading = {
@@ -87,6 +88,7 @@ const heading = {
   color: "#0f172a",
   fontSize: "28px",
   lineHeight: "34px",
+  fontFamily: fontStack,
 };
 
 const intro = {
@@ -94,6 +96,7 @@ const intro = {
   color: "#475569",
   fontSize: "15px",
   lineHeight: "24px",
+  fontFamily: fontStack,
 };
 
 const details = {
@@ -101,6 +104,7 @@ const details = {
   borderRadius: "10px",
   backgroundColor: "#ffffff",
   padding: "18px",
+  fontFamily: fontStack,
 };
 
 const row = {
@@ -108,6 +112,7 @@ const row = {
   color: "#0f172a",
   fontSize: "15px",
   lineHeight: "22px",
+  fontFamily: fontStack,
 };
 
 const messageBox = {
@@ -116,6 +121,7 @@ const messageBox = {
   borderRadius: "10px",
   backgroundColor: "#ffffff",
   padding: "18px",
+  fontFamily: fontStack,
 };
 
 const label = {
@@ -125,6 +131,7 @@ const label = {
   fontWeight: 700,
   letterSpacing: "0.04em",
   textTransform: "uppercase" as const,
+  fontFamily: fontStack,
 };
 
 const messageText = {
@@ -133,6 +140,7 @@ const messageText = {
   fontSize: "15px",
   lineHeight: "24px",
   whiteSpace: "pre-wrap" as const,
+  fontFamily: fontStack,
 };
 
 const footer = {
@@ -140,4 +148,5 @@ const footer = {
   color: "#64748b",
   fontSize: "13px",
   lineHeight: "20px",
+  fontFamily: fontStack,
 };
diff --git a/src/emails/DutyReminderEmail.tsx b/src/emails/DutyReminderEmail.tsx
index ed9128f..4983e83 100644
--- a/src/emails/DutyReminderEmail.tsx
+++ b/src/emails/DutyReminderEmail.tsx
@@ -10,6 +10,8 @@ import {
   Text,
 } from "@react-email/components";
 
+import { fontStack } from "./_styles";
+
 type DutyReminderEmailProps = {
   familyName: string;
   dutyName: string;
@@ -25,15 +27,15 @@ export function DutyReminderEmail({
     <Html lang="de">
       <Head />
       <Preview>
-        Erinnerung: {familyName} ist diese Woche fuer {dutyName} eingeteilt.
+        Erinnerung: {familyName} ist diese Woche für {dutyName} eingeteilt.
       </Preview>
       <Body style={styles.body}>
         <Container style={styles.container}>
           <Section style={styles.header}>
             <Text style={styles.kicker}>Elterndienst</Text>
-            <Heading style={styles.heading}>Danke fuer eure Hilfe</Heading>
+            <Heading style={styles.heading}>Danke für eure Hilfe</Heading>
             <Text style={styles.lead}>
-              Hallo {familyName}, diese Woche seid ihr fuer den Dienst{" "}
+              Hallo {familyName}, diese Woche seid ihr für den Dienst{" "}
               <strong>{dutyName}</strong> eingeteilt.
             </Text>
           </Section>
@@ -43,7 +45,7 @@ export function DutyReminderEmail({
               Zeitraum: <strong>{weekLabel}</strong>
             </Text>
             <Text style={styles.text}>
-              Danke, dass ihr mithelft, den Kita-Alltag verlaesslich zu
+              Danke, dass ihr mithelft, den Kita-Alltag verlässlich zu
               organisieren.
             </Text>
           </Section>
@@ -62,7 +64,7 @@ const styles = {
   body: {
     margin: 0,
     backgroundColor: "#f7f5ef",
-    fontFamily: '-apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif',
+    fontFamily: fontStack,
     color: "#24231f",
   },
   container: {
@@ -70,11 +72,13 @@ const styles = {
     maxWidth: "600px",
     margin: "0 auto",
     padding: "32px 20px",
+    fontFamily: fontStack,
   },
   header: {
     padding: "28px",
     backgroundColor: "#27423a",
     borderRadius: "8px 8px 0 0",
+    fontFamily: fontStack,
   },
   kicker: {
     margin: "0 0 20px",
@@ -83,6 +87,7 @@ const styles = {
     fontWeight: 800,
     letterSpacing: "0.08em",
     textTransform: "uppercase" as const,
+    fontFamily: fontStack,
   },
   heading: {
     margin: "0 0 12px",
@@ -90,12 +95,14 @@ const styles = {
     fontSize: "30px",
     lineHeight: "1.18",
     fontWeight: 800,
+    fontFamily: fontStack,
   },
   lead: {
     margin: 0,
     color: "#eef4eb",
     fontSize: "16px",
     lineHeight: "1.55",
+    fontFamily: fontStack,
   },
   card: {
     padding: "28px",
@@ -103,12 +110,14 @@ const styles = {
     border: "1px solid #dde3d7",
     borderTop: "0",
     borderRadius: "0 0 8px 8px",
+    fontFamily: fontStack,
   },
   text: {
     margin: "0 0 16px",
     color: "#3d423b",
     fontSize: "16px",
     lineHeight: "1.65",
+    fontFamily: fontStack,
   },
   hr: {
     margin: "24px 0",
@@ -120,5 +129,6 @@ const styles = {
     fontSize: "12px",
     lineHeight: "1.5",
     textAlign: "center" as const,
+    fontFamily: fontStack,
   },
 };
diff --git a/src/emails/InviteEmail.tsx b/src/emails/InviteEmail.tsx
index 5207e01..b0528d5 100644
--- a/src/emails/InviteEmail.tsx
+++ b/src/emails/InviteEmail.tsx
@@ -11,6 +11,8 @@ import {
   Text,
 } from "@react-email/components";
 
+import { baseBodyStyle, colors, fontStack } from "./_styles";
+
 type InviteEmailProps = {
   parentName: string;
   kitaName: string;
@@ -25,7 +27,7 @@ export function InviteEmail({
   return (
     <Html lang="de">
       <Head />
-      <Preview>Aktiviere deinen Kita-Planer Account fuer {kitaName}</Preview>
+      <Preview>Aktiviere deinen Kita-Planer Account für {kitaName}</Preview>
       <Body style={styles.body}>
         <Container style={styles.container}>
           <Section style={styles.header}>
@@ -38,7 +40,7 @@ export function InviteEmail({
 
           <Section style={styles.card}>
             <Text style={styles.text}>
-              Ueber den folgenden Link kannst du dein Passwort setzen und deinen
+              Über den folgenden Link kannst du dein Passwort setzen und deinen
               Account aktivieren. Danach hast du Zugriff auf die Kita-Planung,
               Termine und deine Familiendaten.
             </Text>
@@ -66,90 +68,95 @@ export function InviteEmail({
 }
 
 const styles = {
-  body: {
-    margin: 0,
-    backgroundColor: "#f6f7f2",
-    fontFamily:
-      '-apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif',
-    color: "#1f2a24",
-  },
+  body: baseBodyStyle,
   container: {
     width: "100%",
     maxWidth: "600px",
     margin: "0 auto",
     padding: "32px 20px",
+    fontFamily: fontStack,
   },
   header: {
     padding: "28px 28px 20px",
-    backgroundColor: "#1f3b2d",
+    backgroundColor: colors.brandGreen,
     borderRadius: "8px 8px 0 0",
+    fontFamily: fontStack,
   },
   brand: {
     margin: "0 0 28px",
-    color: "#d8f2bd",
+    color: colors.eyebrow,
     fontSize: "13px",
     fontWeight: 700,
     letterSpacing: "0.08em",
     textTransform: "uppercase" as const,
+    fontFamily: fontStack,
   },
   heading: {
     margin: "0 0 12px",
-    color: "#ffffff",
+    color: colors.textHeader,
     fontSize: "30px",
     lineHeight: "1.18",
     fontWeight: 800,
+    fontFamily: fontStack,
   },
   lead: {
     margin: 0,
-    color: "#e7f3e6",
+    color: colors.lead,
     fontSize: "16px",
     lineHeight: "1.55",
+    fontFamily: fontStack,
   },
   card: {
     padding: "28px",
-    backgroundColor: "#ffffff",
+    backgroundColor: colors.cardBg,
     borderRadius: "0 0 8px 8px",
-    border: "1px solid #e0e5dc",
+    border: `1px solid ${colors.border}`,
     borderTop: "0",
+    fontFamily: fontStack,
   },
   text: {
     margin: "0 0 24px",
-    color: "#344139",
+    color: colors.textBody,
     fontSize: "16px",
     lineHeight: "1.65",
+    fontFamily: fontStack,
   },
   button: {
     display: "inline-block",
     padding: "14px 22px",
-    backgroundColor: "#f0b84b",
-    color: "#172119",
+    backgroundColor: colors.brandGreen,
+    color: "#ffffff",
     borderRadius: "6px",
     fontSize: "15px",
-    fontWeight: 800,
+    fontWeight: 700,
     textDecoration: "none",
+    fontFamily: fontStack,
   },
   fallbackText: {
     margin: "28px 0 8px",
-    color: "#66736b",
+    color: colors.textMuted,
     fontSize: "13px",
     lineHeight: "1.5",
+    fontFamily: fontStack,
   },
   linkText: {
     margin: 0,
-    color: "#2f6b4f",
+    color: colors.link,
     fontSize: "13px",
     lineHeight: "1.5",
     wordBreak: "break-all" as const,
+    fontFamily: fontStack,
   },
   hr: {
     margin: "24px 0",
-    borderColor: "#dfe5d9",
+    borderColor: colors.hr,
   },
   footer: {
     margin: 0,
-    color: "#7b857d",
+    color: colors.textFaint,
     fontSize: "12px",
     lineHeight: "1.5",
     textAlign: "center" as const,
+    fontFamily: fontStack,
   },
 };
diff --git a/src/emails/NewsEmail.tsx b/src/emails/NewsEmail.tsx
index 4ac393d..22892f8 100644
--- a/src/emails/NewsEmail.tsx
+++ b/src/emails/NewsEmail.tsx
@@ -11,6 +11,8 @@ import {
   Text,
 } from "@react-email/components";
 
+import { fontStack } from "./_styles";
+
 type NewsEmailProps = {
   title: string;
   content: string;
@@ -53,7 +55,7 @@ const styles = {
   body: {
     margin: 0,
     backgroundColor: "#f5f3ee",
-    fontFamily: '-apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif',
+    fontFamily: fontStack,
     color: "#25231f",
   },
   container: {
@@ -61,11 +63,13 @@ const styles = {
     maxWidth: "600px",
     margin: "0 auto",
     padding: "32px 20px",
+    fontFamily: fontStack,
   },
   header: {
     padding: "28px",
     backgroundColor: "#243b36",
     borderRadius: "8px 8px 0 0",
+    fontFamily: fontStack,
   },
   kicker: {
     margin: "0 0 20px",
@@ -74,6 +78,7 @@ const styles = {
     fontWeight: 800,
     letterSpacing: "0.08em",
     textTransform: "uppercase" as const,
+    fontFamily: fontStack,
   },
   heading: {
     margin: 0,
@@ -81,6 +86,7 @@ const styles = {
     fontSize: "28px",
     lineHeight: "1.2",
     fontWeight: 800,
+    fontFamily: fontStack,
   },
   card: {
     padding: "28px",
@@ -88,6 +94,7 @@ const styles = {
     border: "1px solid #deded5",
     borderTop: "0",
     borderRadius: "0 0 8px 8px",
+    fontFamily: fontStack,
   },
   text: {
     margin: "0 0 24px",
@@ -95,16 +102,18 @@ const styles = {
     fontSize: "15px",
     lineHeight: "1.65",
     whiteSpace: "pre-wrap" as const,
+    fontFamily: fontStack,
   },
   button: {
     display: "inline-block",
     padding: "13px 20px",
-    backgroundColor: "#f0b84b",
-    color: "#172119",
+    backgroundColor: "#243b36",
+    color: "#ffffff",
     borderRadius: "6px",
     fontSize: "15px",
-    fontWeight: 800,
+    fontWeight: 700,
     textDecoration: "none",
+    fontFamily: fontStack,
   },
   hr: {
     margin: "24px 0",
@@ -116,5 +125,6 @@ const styles = {
     fontSize: "12px",
     lineHeight: "1.5",
     textAlign: "center" as const,
+    fontFamily: fontStack,
   },
 };
diff --git a/src/emails/_styles.ts b/src/emails/_styles.ts
new file mode 100644
index 0000000..5220e47
--- /dev/null
+++ b/src/emails/_styles.ts
@@ -0,0 +1,39 @@
+// Gemeinsame Style-Tokens für alle E-Mail-Templates.
+//
+// Schriftart: Mail-Clients fallen unterschiedlich zurück, wenn ein Font nicht
+// verfügbar ist. Manche (z.B. einige Web-Reader) wählen dann Monospace —
+// deshalb erst Arial/Helvetica voranstellen, die praktisch überall existieren.
+// Außerdem wird `fontFamily` auf einzelne Elemente gesetzt statt nur auf
+// `<Body>`, weil Outlook & Co. die Body-CSS oft nicht erben.
+export const fontStack =
+  'Arial, Helvetica, "Segoe UI", -apple-system, BlinkMacSystemFont, Roboto, sans-serif';
+
+export const colors = {
+  brandGreen: "#1f3b2d",
+  brandGreenAccent: "#2f6b4f",
+  bgSoft: "#f6f7f2",
+  bgAlt: "#f8faf8",
+  cardBg: "#ffffff",
+  border: "#e0e5dc",
+  hr: "#dfe5d9",
+  textHeader: "#ffffff",
+  textPrimary: "#1f2a24",
+  textBody: "#344139",
+  textMuted: "#66736b",
+  textFaint: "#7b857d",
+  link: "#2f6b4f",
+  eyebrow: "#d8f2bd",
+  lead: "#e7f3e6",
+};
+
+export const baseBodyStyle = {
+  margin: 0,
+  backgroundColor: colors.bgSoft,
+  fontFamily: fontStack,
+  color: colors.textPrimary,
+} as const;
+
+export const baseTextStyle = {
+  fontFamily: fontStack,
+  color: colors.textBody,
+} as const;