diff --git a/frontend/src/app.css b/frontend/src/app.css
index e19d511..f89aef8 100644
--- a/frontend/src/app.css
+++ b/frontend/src/app.css
@@ -1231,21 +1231,52 @@ a.analysis-split__nav-item {
 }
 
 /* Form-Modale: Overlay + Panel (Desktop zentriert, Mobile Vollbild) */
+html.modal-scroll-locked {
+  overflow: hidden;
+  overscroll-behavior: none;
+  height: 100%;
+}
+html.modal-scroll-locked body {
+  overflow: hidden !important;
+  overscroll-behavior: none;
+}
+html.modal-scroll-locked .app-shell,
+html.modal-scroll-locked .app-shell__column {
+  overflow: hidden;
+}
+html.modal-scroll-locked .app-main {
+  overflow: hidden !important;
+  overscroll-behavior: none;
+}
+
 .modal-overlay--form {
   position: fixed;
   inset: 0;
   z-index: 1000;
   background: rgba(0, 0, 0, 0.5);
   display: flex;
+  flex-direction: column;
   align-items: center;
   justify-content: center;
   padding: 1rem;
   overflow: hidden;
+  overscroll-behavior: none;
+  touch-action: none;
   box-sizing: border-box;
+  width: 100%;
+  max-width: 100vw;
 }
 .modal-overlay--form.modal-overlay--raised {
   z-index: 1100;
 }
+.modal-overlay__focus-catcher {
+  position: absolute;
+  width: 0;
+  height: 0;
+  overflow: hidden;
+  opacity: 0;
+  pointer-events: none;
+}
 .modal-panel--form {
   display: flex;
   flex-direction: column;
@@ -1259,6 +1290,10 @@ a.analysis-split__nav-item {
   min-height: 0;
   min-width: 0;
   box-sizing: border-box;
+  touch-action: manipulation;
+  flex: 0 1 auto;
+  margin: auto;
+  align-self: center;
 }
 .modal-panel--form.modal-panel--narrow {
   max-width: min(560px, 100%);
@@ -1295,7 +1330,9 @@ a.analysis-split__nav-item {
   min-width: 0;
   overflow-x: hidden;
   overflow-y: auto;
+  overscroll-behavior: contain;
   overscroll-behavior-x: none;
+  touch-action: pan-y;
   -webkit-overflow-scrolling: touch;
   padding-bottom: 4px;
 }
@@ -1309,13 +1346,24 @@ a.analysis-split__nav-item {
   .modal-overlay--form {
     padding: 0;
     align-items: stretch;
+    justify-content: stretch;
+    width: 100vw;
+    max-width: 100vw;
+    left: 0;
+    right: 0;
   }
   .modal-panel--form {
     max-width: 100%;
+    width: 100%;
     max-height: 100dvh;
     height: 100dvh;
     border-radius: 0;
+    margin: 0;
+    flex: 1 1 auto;
+    align-self: stretch;
     padding: 12px;
+    padding-left: max(12px, env(safe-area-inset-left, 0px));
+    padding-right: max(12px, env(safe-area-inset-right, 0px));
     padding-top: max(12px, env(safe-area-inset-top, 0px));
     padding-bottom: max(0px, env(safe-area-inset-bottom, 0px));
   }
diff --git a/frontend/src/components/FormModalOverlay.jsx b/frontend/src/components/FormModalOverlay.jsx
new file mode 100644
index 0000000..6365ae6
--- /dev/null
+++ b/frontend/src/components/FormModalOverlay.jsx
@@ -0,0 +1,56 @@
+import React, { useEffect, useRef } from 'react'
+import { createPortal } from 'react-dom'
+import { useModalScrollLock } from '../hooks/useModalScrollLock'
+
+/**
+ * Formular-Modal am document.body (Portal) — volle Viewport-Breite, kein Hintergrund-Scroll.
+ */
+export default function FormModalOverlay({
+  open,
+  children,
+  raised = false,
+  className = '',
+  onBackdropClick,
+  'data-testid': testId,
+}) {
+  const overlayRef = useRef(null)
+  useModalScrollLock(open)
+
+  useEffect(() => {
+    if (!open) return undefined
+    const t = window.setTimeout(() => {
+      overlayRef.current?.focus({ preventScroll: true })
+    }, 0)
+    return () => clearTimeout(t)
+  }, [open])
+
+  if (!open) return null
+
+  const overlayClass = [
+    'modal-overlay',
+    'modal-overlay--form',
+    raised ? 'modal-overlay--raised' : '',
+    className,
+  ]
+    .filter(Boolean)
+    .join(' ')
+
+  return createPortal(
+    <div
+      ref={overlayRef}
+      tabIndex={-1}
+      data-testid={testId}
+      className={overlayClass}
+      onClick={
+        onBackdropClick
+          ? (e) => {
+              if (e.target === e.currentTarget) onBackdropClick()
+            }
+          : undefined
+      }
+    >
+      {children}
+    </div>,
+    document.body,
+  )
+}
diff --git a/frontend/src/components/planning/SaveExercisesAsModuleModal.jsx b/frontend/src/components/planning/SaveExercisesAsModuleModal.jsx
index a2d58a9..ee2c119 100644
--- a/frontend/src/components/planning/SaveExercisesAsModuleModal.jsx
+++ b/frontend/src/components/planning/SaveExercisesAsModuleModal.jsx
@@ -1,6 +1,7 @@
 import React, { useCallback, useEffect, useMemo, useState } from 'react'
 import { useNavigate } from 'react-router-dom'
 import FormActionBar from '../FormActionBar'
+import FormModalOverlay from '../FormModalOverlay'
 import api from '../../utils/api'
 import { useToast } from '../../context/ToastContext'
 import { useAuth } from '../../context/AuthContext'
@@ -147,7 +148,7 @@ export default function SaveExercisesAsModuleModal({
   if (!open) return null
 
   return (
-    <div className="modal-overlay modal-overlay--form modal-overlay--raised">
+    <FormModalOverlay open={open} raised onBackdropClick={onClose}>
       <div className="card modal-panel--form modal-panel--narrow">
         <h2 className="modal-panel__title">Übungen als Trainingsmodul</h2>
         <p className="modal-panel__intro">
@@ -306,6 +307,6 @@ export default function SaveExercisesAsModuleModal({
           </div>
         ) : null}
       </div>
-    </div>
+    </FormModalOverlay>
   )
 }
diff --git a/frontend/src/components/planning/TrainingPlanningUnitFormModal.jsx b/frontend/src/components/planning/TrainingPlanningUnitFormModal.jsx
index b15004a..7622624 100644
--- a/frontend/src/components/planning/TrainingPlanningUnitFormModal.jsx
+++ b/frontend/src/components/planning/TrainingPlanningUnitFormModal.jsx
@@ -1,6 +1,7 @@
 import React, { useEffect, useMemo, useState } from 'react'
 import { Link } from 'react-router-dom'
 import FormActionBar from '../FormActionBar'
+import FormModalOverlay from '../FormModalOverlay'
 import TrainingPlanExerciseVisibilityPanel from '../TrainingPlanExerciseVisibilityPanel'
 import TrainingUnitSectionsEditor from '../TrainingUnitSectionsEditor'
 import { activeClubMemberships } from '../../utils/activeClub'
@@ -57,7 +58,7 @@ export default function TrainingPlanningUnitFormModal({
   const formId = 'planning-unit-form'
 
   return (
-    <div data-testid="planning-unit-form-modal" className="modal-overlay modal-overlay--form">
+    <FormModalOverlay open={open} data-testid="planning-unit-form-modal" onBackdropClick={onCancel}>
       <div className="modal-panel--form">
         <h2 className="modal-panel__title">
           {editingUnit ? 'Trainingseinheit bearbeiten' : 'Neue Trainingseinheit'}
@@ -575,6 +576,6 @@ export default function TrainingPlanningUnitFormModal({
           />
         </form>
       </div>
-    </div>
+    </FormModalOverlay>
   )
 }
diff --git a/frontend/src/components/planning/TrainingPublishToFrameworkModal.jsx b/frontend/src/components/planning/TrainingPublishToFrameworkModal.jsx
index 3789013..c7714d6 100644
--- a/frontend/src/components/planning/TrainingPublishToFrameworkModal.jsx
+++ b/frontend/src/components/planning/TrainingPublishToFrameworkModal.jsx
@@ -1,6 +1,7 @@
 import React, { useEffect, useState, useMemo } from 'react'
 import { useNavigate } from 'react-router-dom'
 import FormActionBar from '../FormActionBar'
+import FormModalOverlay from '../FormModalOverlay'
 import api from '../../utils/api'
 import { useToast } from '../../context/ToastContext'
 import { useAuth } from '../../context/AuthContext'
@@ -192,7 +193,7 @@ export default function TrainingPublishToFrameworkModal({
   if (!open) return null
 
   return (
-    <div className="modal-overlay modal-overlay--form modal-overlay--raised">
+    <FormModalOverlay open={open} raised onBackdropClick={resetAndClose}>
       <div className="card modal-panel--form modal-panel--narrow">
         <h2 className="modal-panel__title">Ablauf ins Rahmenprogramm übernehmen</h2>
         <p className="modal-panel__intro">
@@ -400,6 +401,6 @@ export default function TrainingPublishToFrameworkModal({
           />
         </form>
       </div>
-    </div>
+    </FormModalOverlay>
   )
 }
diff --git a/frontend/src/hooks/useModalScrollLock.js b/frontend/src/hooks/useModalScrollLock.js
new file mode 100644
index 0000000..181dbeb
--- /dev/null
+++ b/frontend/src/hooks/useModalScrollLock.js
@@ -0,0 +1,60 @@
+import { useEffect } from 'react'
+
+let lockDepth = 0
+const saved = {
+  appMainScrollTop: 0,
+  bodyScrollTop: 0,
+  appMainOverflow: '',
+  appMainTouchAction: '',
+}
+
+function queryAppMain() {
+  return document.querySelector('.app-main')
+}
+
+function applyLock() {
+  document.documentElement.classList.add('modal-scroll-locked')
+
+  const appMain = queryAppMain()
+  if (appMain) {
+    saved.appMainScrollTop = appMain.scrollTop
+    saved.appMainOverflow = appMain.style.overflow
+    saved.appMainTouchAction = appMain.style.touchAction
+    appMain.style.overflow = 'hidden'
+    appMain.style.touchAction = 'none'
+  }
+
+  saved.bodyScrollTop = window.scrollY || document.documentElement.scrollTop || 0
+  document.body.style.overflow = 'hidden'
+  document.body.style.overscrollBehavior = 'none'
+}
+
+function releaseLock() {
+  document.documentElement.classList.remove('modal-scroll-locked')
+
+  const appMain = queryAppMain()
+  if (appMain) {
+    appMain.style.overflow = saved.appMainOverflow
+    appMain.style.touchAction = saved.appMainTouchAction
+    appMain.scrollTop = saved.appMainScrollTop
+  }
+
+  document.body.style.overflow = ''
+  document.body.style.overscrollBehavior = ''
+  if (saved.bodyScrollTop) {
+    window.scrollTo(0, saved.bodyScrollTop)
+  }
+}
+
+/** Hintergrund-Scroll sperren (.app-main + body), verschachtelte Modals via Zähler. */
+export function useModalScrollLock(active) {
+  useEffect(() => {
+    if (!active) return undefined
+    lockDepth += 1
+    if (lockDepth === 1) applyLock()
+    return () => {
+      lockDepth = Math.max(0, lockDepth - 1)
+      if (lockDepth === 0) releaseLock()
+    }
+  }, [active])
+}