refactor(ui): update layout styles for AppContent and AccountView components

- Changed layout from grid to flex in AccountView for improved responsiveness and alignment.
- Adjusted flex properties in AppContent to ensure proper scrolling behavior and height management.
- Enhanced styling for account settings panel to support better content overflow handling and visual consistency.

frontend/src/components/AppContent.vue

@@ -45,8 +45,9 @@
   flex-direction: column;
 }
 
+/* flex-basis 0: Höhe richtet sich nach verbleibendem Platz, nicht nach Inhalt (sonst kein Scroll) */
 .app-content__inner > :last-child {
-  flex: 1 1 auto;
+  flex: 1 1 0%;
   min-height: 0;
 }
 

frontend/src/views/settings/AccountView.vue

@@ -225,14 +225,14 @@ export default {
 
 <style lang="scss" scoped>
 .account-settings {
-    display: grid;
+    display: flex;
+    flex-direction: column;
     gap: 18px;
     max-width: 960px;
-    /* Flex-Kind von .app-content__inner: ohne overflow wird Inhalt bei min-height:0 abgeschnitten */
+    width: 100%;
     min-height: 0;
-    overflow-y: auto;
-    align-content: start;
-    -webkit-overflow-scrolling: touch;
+    flex: 1 1 0%;
+    align-self: stretch;
 }
 
 .account-settings__hero,
@@ -244,6 +244,7 @@ export default {
 }
 
 .account-settings__hero {
+    flex: 0 0 auto;
     padding: 26px 28px;
 }
 
@@ -265,8 +266,14 @@ export default {
     color: var(--color-text-secondary);
 }
 
-.account-settings__panel {
+/* Unteres Panel: füllt Resthöhe und scrollt (global .surface-card hat overflow:hidden) */
+.account-settings__panel.account-settings__panel {
+    flex: 1 1 0%;
+    min-height: 0;
     padding: 24px;
+    overflow-x: hidden;
+    overflow-y: auto;
+    -webkit-overflow-scrolling: touch;
 }
 
 .account-settings__grid {