diff --git a/.env b/.env
index b33182d..91dff9a 100644
--- a/.env
+++ b/.env
@@ -11,5 +11,5 @@
 
 DATABASE_URL="file:./dev.db"
 
-NEXTAUTH_URL=http://localhost:3000
+NEXT_PUBLIC_APP_URL=https://10.0.1.25
 NEXTAUTH_SECRET=tegvideo7010!
\ No newline at end of file
diff --git a/app/(app)/devices/DeviceCreateModal.tsx b/app/(app)/devices/DeviceCreateModal.tsx
new file mode 100644
index 0000000..dee3d27
--- /dev/null
+++ b/app/(app)/devices/DeviceCreateModal.tsx
@@ -0,0 +1,405 @@
+'use client';
+
+import {
+  ChangeEvent,
+  Dispatch,
+  SetStateAction,
+  useCallback,
+  useEffect,
+  useState,
+} from 'react';
+import Modal from '@/components/ui/Modal';
+import { PlusIcon } from '@heroicons/react/24/outline';
+import TagMultiCombobox, { TagOption } from '@/components/ui/TagMultiCombobox';
+import Button from '@/components/ui/Button';
+import type { DeviceDetail } from './page';
+
+type DeviceCreateModalProps = {
+  open: boolean;
+  onClose: () => void;
+  onCreated: (device: DeviceDetail) => void;
+  allTags: TagOption[];
+  setAllTags: Dispatch<SetStateAction<TagOption[]>>;
+};
+
+type NewDevice = {
+  inventoryNumber: string;
+  name: string;
+  manufacturer: string;
+  model: string;
+  serialNumber: string | null;
+  productNumber: string | null;
+  comment: string | null;
+  group: string | null;
+  location: string | null;
+  ipv4Address: string | null;
+  ipv6Address: string | null;
+  macAddress: string | null;
+  username: string | null;
+  passwordHash: string | null;
+  tags: string[];
+};
+
+const emptyDevice: NewDevice = {
+  inventoryNumber: '',
+  name: '',
+  manufacturer: '',
+  model: '',
+  serialNumber: null,
+  productNumber: null,
+  comment: null,
+  group: null,
+  location: null,
+  ipv4Address: null,
+  ipv6Address: null,
+  macAddress: null,
+  username: null,
+  passwordHash: null,
+  tags: [],
+};
+
+export default function DeviceCreateModal({
+  open,
+  onClose,
+  onCreated,
+  allTags,
+  setAllTags,
+}: DeviceCreateModalProps) {
+  const [form, setForm] = useState<NewDevice>(emptyDevice);
+  const [saveLoading, setSaveLoading] = useState(false);
+  const [error, setError] = useState<string | null>(null);
+
+  // Formular resetten, wenn Modal neu geöffnet wird
+  useEffect(() => {
+    if (open) {
+      setForm(emptyDevice);
+      setError(null);
+      setSaveLoading(false);
+    }
+  }, [open]);
+
+  const handleFieldChange = (
+    field: keyof NewDevice,
+    e: ChangeEvent<HTMLInputElement | HTMLTextAreaElement>,
+  ) => {
+    const value = e.target.value;
+    setForm((prev) => ({
+      ...prev,
+      [field]: value === '' && prev[field] === null ? null : value,
+    }));
+  };
+
+  const handleSave = useCallback(async () => {
+    if (!form.inventoryNumber.trim() || !form.name.trim()) {
+      setError('Bitte mindestens Inventar-Nr. und Bezeichnung ausfüllen.');
+      return;
+    }
+
+    setSaveLoading(true);
+    setError(null);
+
+    try {
+      const res = await fetch('/api/devices', {
+        method: 'POST',
+        headers: { 'Content-Type': 'application/json' },
+        body: JSON.stringify({
+          inventoryNumber: form.inventoryNumber.trim(),
+          name: form.name.trim(),
+          manufacturer: form.manufacturer || '',
+          model: form.model || '',
+          serialNumber: form.serialNumber || null,
+          productNumber: form.productNumber || null,
+          comment: form.comment || null,
+          group: form.group || null,
+          location: form.location || null,
+          ipv4Address: form.ipv4Address || null,
+          ipv6Address: form.ipv6Address || null,
+          macAddress: form.macAddress || null,
+          username: form.username || null,
+          passwordHash: form.passwordHash || null,
+          tags: form.tags ?? [],
+        }),
+      });
+
+      if (!res.ok) {
+        if (res.status === 409) {
+          throw new Error(
+            'Es existiert bereits ein Gerät mit dieser Inventar-Nr.',
+          );
+        }
+        throw new Error('Anlegen des Geräts ist fehlgeschlagen.');
+      }
+
+      const created = (await res.json()) as DeviceDetail;
+      onCreated(created);
+      onClose();
+    } catch (err: any) {
+      console.error('Error creating device', err);
+      setError(
+        err instanceof Error
+          ? err.message
+          : 'Netzwerkfehler beim Anlegen des Geräts.',
+      );
+    } finally {
+      setSaveLoading(false);
+    }
+  }, [form, onCreated, onClose]);
+
+  const handleClose = () => {
+    if (saveLoading) return;
+    onClose();
+  };
+
+  return (
+    <Modal
+      open={open}
+      onClose={handleClose}
+      title="Neues Gerät anlegen"
+      icon={<PlusIcon className="size-6" />}
+      tone="info"
+      variant="centered"
+      size="sm"
+      footer={
+        <div className="px-4 py-3 sm:px-6 sm:flex sm:flex-row-reverse sm:gap-3">
+          <Button
+            type="button"
+            onClick={handleSave}
+            size="md"
+            fullWidth
+            variant="primary"
+            tone="indigo"
+            disabled={saveLoading}
+            className="sm:w-auto"
+          >
+            {saveLoading ? 'Anlegen …' : 'Anlegen'}
+          </Button>
+
+          <Button
+            type="button"
+            onClick={handleClose}
+            size="md"
+            variant="secondary"
+            tone="gray"
+            className="mt-3 sm:mt-0 sm:w-auto"
+          >
+            Abbrechen
+          </Button>
+        </div>
+      }
+    >
+      {error && (
+        <p className="mb-3 text-sm text-red-600 dark:text-red-400">
+          {error}
+        </p>
+      )}
+
+      {/* Body wie bei DeviceDetailModal: einfach Inhalt, Scroll kommt vom Modal */}
+      <div className="pr-2 grid grid-cols-1 gap-4 text-sm sm:grid-cols-2">
+        {/* Inventarnummer */}
+        <div>
+          <p className="text-xs font-semibold uppercase tracking-wide text-gray-400">
+            Inventar-Nr. *
+          </p>
+          <input
+            type="text"
+            className="mt-1 block w-full rounded-md border-0 bg-gray-900/40 px-2.5 py-1.5 text-sm text-gray-100 shadow-xs ring-1 ring-inset ring-gray-700 placeholder:text-gray-400 focus:ring-2 focus:ring-indigo-500 focus:outline-none"
+            value={form.inventoryNumber}
+            onChange={(e) => handleFieldChange('inventoryNumber', e)}
+          />
+        </div>
+
+        {/* Bezeichnung */}
+        <div>
+          <p className="text-xs font-semibold uppercase tracking-wide text-gray-400">
+            Bezeichnung *
+          </p>
+          <input
+            type="text"
+            className="mt-1 block w-full rounded-md border-0 bg-gray-900/40 px-2.5 py-1.5 text-sm text-gray-100 shadow-xs ring-1 ring-inset ring-gray-700 placeholder:text-gray-400 focus:ring-2 focus:ring-indigo-500 focus:outline-none"
+            value={form.name}
+            onChange={(e) => handleFieldChange('name', e)}
+          />
+        </div>
+
+        {/* Hersteller / Modell */}
+        <div>
+          <p className="text-xs font-semibold uppercase tracking-wide text-gray-400">
+            Hersteller
+          </p>
+          <input
+            type="text"
+            className="mt-1 block w-full rounded-md border-0 bg-gray-900/40 px-2.5 py-1.5 text-sm text-gray-100 shadow-xs ring-1 ring-inset ring-gray-700 placeholder:text-gray-400 focus:ring-2 focus:ring-indigo-500 focus:outline-none"
+            value={form.manufacturer}
+            onChange={(e) => handleFieldChange('manufacturer', e)}
+          />
+        </div>
+
+        <div>
+          <p className="text-xs font-semibold uppercase tracking-wide text-gray-400">
+            Modell
+          </p>
+          <input
+            type="text"
+            className="mt-1 block w-full rounded-md border-0 bg-gray-900/40 px-2.5 py-1.5 text-sm text-gray-100 shadow-xs ring-1 ring-inset ring-gray-700 placeholder:text-gray-400 focus:ring-2 focus:ring-indigo-500 focus:outline-none"
+            value={form.model}
+            onChange={(e) => handleFieldChange('model', e)}
+          />
+        </div>
+
+        {/* Seriennummer / Produktnummer */}
+        <div>
+          <p className="text-xs font-semibold uppercase tracking-wide text-gray-400">
+            Seriennummer
+          </p>
+          <input
+            type="text"
+            className="mt-1 block w-full rounded-md border-0 bg-gray-900/40 px-2.5 py-1.5 text-sm text-gray-100 shadow-xs ring-1 ring-inset ring-gray-700 placeholder:text-gray-400 focus:ring-2 focus:ring-indigo-500 focus:outline-none"
+            value={form.serialNumber ?? ''}
+            onChange={(e) => handleFieldChange('serialNumber', e)}
+          />
+        </div>
+
+        <div>
+          <p className="text-xs font-semibold uppercase tracking-wide text-gray-400">
+            Produktnummer
+          </p>
+          <input
+            type="text"
+            className="mt-1 block w-full rounded-md border-0 bg-gray-900/40 px-2.5 py-1.5 text-sm text-gray-100 shadow-xs ring-1 ring-inset ring-gray-700 placeholder:text-gray-400 focus:ring-2 focus:ring-indigo-500 focus:outline-none"
+            value={form.productNumber ?? ''}
+            onChange={(e) => handleFieldChange('productNumber', e)}
+          />
+        </div>
+
+        {/* Standort / Gruppe */}
+        <div>
+          <p className="text-xs font-semibold uppercase tracking-wide text-gray-400">
+            Standort / Raum
+          </p>
+          <input
+            type="text"
+            className="mt-1 block w-full rounded-md border-0 bg-gray-900/40 px-2.5 py-1.5 text-sm text-gray-100 shadow-xs ring-1 ring-inset ring-gray-700 placeholder:text-gray-400 focus:ring-2 focus:ring-indigo-500 focus:outline-none"
+            value={form.location ?? ''}
+            onChange={(e) => handleFieldChange('location', e)}
+          />
+        </div>
+
+        <div>
+          <p className="text-xs font-semibold uppercase tracking-wide text-gray-400">
+            Gruppe
+          </p>
+          <input
+            type="text"
+            className="mt-1 block w-full rounded-md border-0 bg-gray-900/40 px-2.5 py-1.5 text-sm text-gray-100 shadow-xs ring-1 ring-inset ring-gray-700 placeholder:text-gray-400 focus:ring-2 focus:ring-indigo-500 focus:outline-none"
+            value={form.group ?? ''}
+            onChange={(e) => handleFieldChange('group', e)}
+          />
+        </div>
+
+        {/* Tags */}
+        <div className="sm:col-span-2">
+          <TagMultiCombobox
+            label="Tags"
+            availableTags={allTags}
+            value={(form.tags ?? []).map((name) => ({ name }))}
+            onChange={(next) => {
+              const names = next.map((t) => t.name);
+
+              setForm((prev) => ({
+                ...prev,
+                tags: names,
+              }));
+
+              setAllTags((prev) => {
+                const map = new Map(prev.map((t) => [t.name.toLowerCase(), t]));
+                for (const t of next) {
+                  const key = t.name.toLowerCase();
+                  if (!map.has(key)) {
+                    map.set(key, t);
+                  }
+                }
+                return Array.from(map.values());
+              });
+            }}
+            placeholder="z.B. Drucker, Serverraum, kritisch"
+          />
+        </div>
+
+        {/* Netzwerkdaten */}
+        <div>
+          <p className="text-xs font-semibold uppercase tracking-wide text-gray-400">
+            IPv4-Adresse
+          </p>
+          <input
+            type="text"
+            className="mt-1 block w-full rounded-md border-0 bg-gray-900/40 px-2.5 py-1.5 text-sm text-gray-100 shadow-xs ring-1 ring-inset ring-gray-700 placeholder:text-gray-400 focus:ring-2 focus:ring-indigo-500 focus:outline-none"
+            value={form.ipv4Address ?? ''}
+            onChange={(e) => handleFieldChange('ipv4Address', e)}
+          />
+        </div>
+
+        <div>
+          <p className="text-xs font-semibold uppercase tracking-wide text-gray-400">
+            IPv6-Adresse
+          </p>
+          <input
+            type="text"
+            className="mt-1 block w-full rounded-md border-0 bg-gray-900/40 px-2.5 py-1.5 text-sm text-gray-100 shadow-xs ring-1 ring-inset ring-gray-700 placeholder:text-gray-400 focus:ring-2 focus:ring-indigo-500 focus:outline-none"
+            value={form.ipv6Address ?? ''}
+            onChange={(e) => handleFieldChange('ipv6Address', e)}
+          />
+        </div>
+
+        <div className="sm:col-span-2">
+          <p className="text-xs font-semibold uppercase tracking-wide text-gray-400">
+            MAC-Adresse
+          </p>
+          <input
+            type="text"
+            className="mt-1 block w-full rounded-md border-0 bg-gray-900/40 px-2.5 py-1.5 text-sm text-gray-100 shadow-xs ring-1 ring-inset ring-gray-700 placeholder:text-gray-400 focus:ring-2 focus:ring-indigo-500 focus:outline-none"
+            value={form.macAddress ?? ''}
+            onChange={(e) => handleFieldChange('macAddress', e)}
+          />
+        </div>
+
+        {/* Zugangsdaten */}
+        <div>
+          <p className="text-xs font-semibold uppercase tracking-wide text-gray-400">
+            Benutzername
+          </p>
+          <input
+            type="text"
+            className="mt-1 block w-full rounded-md border-0 bg-gray-900/40 px-2.5 py-1.5 text-sm text-gray-100 shadow-xs ring-1 ring-inset ring-gray-700 placeholder:text-gray-400 focus:ring-2 focus:ring-indigo-500 focus:outline-none"
+            value={form.username ?? ''}
+            onChange={(e) => handleFieldChange('username', e)}
+          />
+        </div>
+
+        <div>
+          <p className="text-xs font-semibold uppercase tracking-wide text-gray-400">
+            Passwort
+          </p>
+          <input
+            type="password"
+            className="mt-1 block w-full rounded-md border-0 bg-gray-900/40 px-2.5 py-1.5 text-sm text-gray-100 shadow-xs ring-1 ring-inset ring-gray-700 placeholder:text-gray-400 focus:ring-2 focus:ring-indigo-500 focus:outline-none"
+            value={form.passwordHash ?? ''}
+            onChange={(e) => handleFieldChange('passwordHash', e)}
+          />
+        </div>
+
+        {/* Kommentar */}
+        <div className="sm:col-span-2">
+          <p className="text-xs font-semibold uppercase tracking-wide text-gray-400">
+            Kommentar
+          </p>
+          <textarea
+            rows={3}
+            className="mt-1 block w-full rounded-md border-0 bg-gray-900/40 px-2.5 py-1.5 text-sm text-gray-100 shadow-xs ring-1 ring-inset ring-gray-700 placeholder:text-gray-400 focus:ring-2 focus:ring-indigo-500 focus:outline-none"
+            value={form.comment ?? ''}
+            onChange={(e) => handleFieldChange('comment', e)}
+          />
+        </div>
+      </div>
+    </Modal>
+  );
+}
diff --git a/app/(app)/devices/DeviceDetailModal.tsx b/app/(app)/devices/DeviceDetailModal.tsx
new file mode 100644
index 0000000..bbe9955
--- /dev/null
+++ b/app/(app)/devices/DeviceDetailModal.tsx
@@ -0,0 +1,365 @@
+// app/(app)/devices/DeviceDetailModal.tsx
+'use client';
+
+import { useEffect, useState } from 'react';
+import Modal from '@/components/ui/Modal';
+import { BookOpenIcon } from '@heroicons/react/24/outline';
+import DeviceHistorySidebar from './DeviceHistorySidebar';
+import Button from '@/components/ui/Button';
+import type { DeviceDetail } from './page';
+import { DeviceQrCode } from '@/components/DeviceQrCode';
+import Tabs from '@/components/ui/Tabs';
+
+type DeviceDetailModalProps = {
+  open: boolean;
+  inventoryNumber: string | null;
+  onClose: () => void;
+};
+
+const dtf = new Intl.DateTimeFormat('de-DE', {
+  dateStyle: 'short',
+  timeStyle: 'short',
+});
+
+function DeviceDetailsGrid({ device }: { device: DeviceDetail }) {
+  return (
+    <div className="grid grid-cols-1 gap-4 text-sm sm:grid-cols-2">
+      {/* Inventarnummer */}
+      <div>
+        <p className="text-xs font-semibold uppercase tracking-wide text-gray dark:text-gray-500">
+          Inventar-Nr.
+        </p>
+        <p className="mt-1 text-sm text-gray-800 dark:text-gray-400">
+          {device.inventoryNumber}
+        </p>
+      </div>
+
+      {/* Bezeichnung */}
+      <div>
+        <p className="text-xs font-semibold uppercase tracking-wide text-gray dark:text-gray-500">
+          Bezeichnung
+        </p>
+        <p className="mt-1 text-sm text-gray-800 dark:text-gray-400">
+          {device.name || '–'}
+        </p>
+      </div>
+
+      {/* Hersteller / Modell */}
+      <div>
+        <p className="text-xs font-semibold uppercase tracking-wide text-gray dark:text-gray-500">
+          Hersteller
+        </p>
+        <p className="mt-1 text-sm text-gray-800 dark:text-gray-400">
+          {device.manufacturer || '–'}
+        </p>
+      </div>
+
+      <div>
+        <p className="text-xs font-semibold uppercase tracking-wide text-gray dark:text-gray-500">
+          Modell
+        </p>
+        <p className="mt-1 text-sm text-gray-800 dark:text-gray-400">
+          {device.model || '–'}
+        </p>
+      </div>
+
+      {/* Seriennummer / Produktnummer */}
+      <div>
+        <p className="text-xs font-semibold uppercase tracking-wide text-gray dark:text-gray-500">
+          Seriennummer
+        </p>
+        <p className="mt-1 text-sm text-gray-800 dark:text-gray-400">
+          {device.serialNumber || '–'}
+        </p>
+      </div>
+
+      <div>
+        <p className="text-xs font-semibold uppercase tracking-wide text-gray dark:text-gray-500">
+          Produktnummer
+        </p>
+        <p className="mt-1 text-sm text-gray-800 dark:text-gray-400">
+          {device.productNumber || '–'}
+        </p>
+      </div>
+
+      {/* Standort / Gruppe */}
+      <div>
+        <p className="text-xs font-semibold uppercase tracking-wide text-gray dark:text-gray-500">
+          Standort / Raum
+        </p>
+        <p className="mt-1 text-sm text-gray-800 dark:text-gray-400">
+          {device.location || '–'}
+        </p>
+      </div>
+
+      <div>
+        <p className="text-xs font-semibold uppercase tracking-wide text-gray dark:text-gray-500">
+          Gruppe
+        </p>
+        <p className="mt-1 text-sm text-gray-800 dark:text-gray-400">
+          {device.group || '–'}
+        </p>
+      </div>
+
+      {/* Tags */}
+      <div className="sm:col-span-2">
+        <p className="text-xs font-semibold uppercase tracking-wide text-gray dark:text-gray-500">
+          Tags
+        </p>
+        {device.tags && device.tags.length > 0 ? (
+          <div className="mt-1 flex flex-wrap gap-1.5">
+            {device.tags.map((tag) => (
+              <span
+                key={tag}
+                className="inline-flex items-center rounded-full bg-gray-800/60 px-2.5 py-0.5 text-xs font-medium text-gray-100 dark:bg-gray-700/70"
+              >
+                {tag}
+              </span>
+            ))}
+          </div>
+        ) : (
+          <p className="mt-1 text-sm text-gray-800 dark:text-gray-400">–</p>
+        )}
+      </div>
+
+      {/* Netzwerkdaten */}
+      <div>
+        <p className="text-xs font-semibold uppercase tracking-wide text-gray dark:text-gray-500">
+          IPv4-Adresse
+        </p>
+        <p className="mt-1 text-sm text-gray-800 dark:text-gray-400">
+          {device.ipv4Address || '–'}
+        </p>
+      </div>
+
+      <div>
+        <p className="text-xs font-semibold uppercase tracking-wide text-gray dark:text-gray-500">
+          IPv6-Adresse
+        </p>
+        <p className="mt-1 text-sm text-gray-800 dark:text-gray-400">
+          {device.ipv6Address || '–'}
+        </p>
+      </div>
+
+      <div className="sm:col-span-2">
+        <p className="text-xs font-semibold uppercase tracking-wide text-gray dark:text-gray-500">
+          MAC-Adresse
+        </p>
+        <p className="mt-1 text-sm text-gray-800 dark:text-gray-400">
+          {device.macAddress || '–'}
+        </p>
+      </div>
+
+      {/* Zugangsdaten */}
+      <div>
+        <p className="text-xs font-semibold uppercase tracking-wide text-gray dark:text-gray-500">
+          Benutzername
+        </p>
+        <p className="mt-1 text-sm text-gray-800 dark:text-gray-400">
+          {device.username || '–'}
+        </p>
+      </div>
+ 
+      <div>
+        <p className="text-xs font-semibold uppercase tracking-wide text-gray dark:text-gray-500">
+          Passwort (Hash)
+        </p>
+        <p className="mt-1 text-sm text-gray-800 dark:text-gray-400 break-all">
+          {device.passwordHash || '–'}
+        </p>
+      </div>
+
+      {/* Kommentar */}
+      <div className="sm:col-span-2">
+        <p className="text-xs font-semibold uppercase tracking-wide text-gray dark:text-gray-500">
+          Kommentar
+        </p>
+        <div className="mt-1 rounded-md border border-gray-700 bg-gray-400/20 px-2.5 py-2 text-sm text-gray-800 dark:bg-gray-900/40 dark:text-gray-400 dark:border-gray-700">
+          {device.comment && device.comment.trim().length > 0
+            ? device.comment
+            : '–'}
+        </div>
+      </div>
+
+      {/* Metadaten */}
+      <div>
+        <p className="text-xs font-semibold uppercase tracking-wide text-gray dark:text-gray-500">
+          Angelegt am
+        </p>
+        <p className="mt-1 text-sm text-gray-800 dark:text-gray-400">
+          {device.createdAt
+            ? dtf.format(new Date(device.createdAt))
+            : '–'}
+        </p>
+      </div>
+
+      <div>
+        <p className="text-xs font-semibold uppercase tracking-wide text-gray dark:text-gray-500">
+          Zuletzt geändert am
+        </p>
+        <p className="mt-1 text-sm text-gray-800 dark:text-gray-400">
+          {device.updatedAt
+            ? dtf.format(new Date(device.updatedAt))
+            : '–'}
+        </p>
+      </div>
+    </div>
+  );
+}
+
+export default function DeviceDetailModal({
+  open,
+  inventoryNumber,
+  onClose,
+}: DeviceDetailModalProps) {
+  const [device, setDevice] = useState<DeviceDetail | null>(null);
+  const [loading, setLoading] = useState(false);
+  const [error, setError] = useState<string | null>(null);
+  const [activeTab, setActiveTab] = useState<'details' | 'history'>('details');
+
+  useEffect(() => {
+    if (!open || !inventoryNumber) return;
+
+    const inv = inventoryNumber;
+    let cancelled = false;
+
+    setLoading(true);
+    setError(null);
+    setDevice(null);
+
+    async function loadDevice() {
+      try {
+        const res = await fetch(`/api/devices/${encodeURIComponent(inv)}`, {
+          method: 'GET',
+          headers: { 'Content-Type': 'application/json' },
+          cache: 'no-store',
+        });
+
+        if (!res.ok) {
+          if (res.status === 404) {
+            throw new Error('Gerät wurde nicht gefunden.');
+          }
+          throw new Error('Beim Laden der Gerätedaten ist ein Fehler aufgetreten.');
+        }
+
+        const data = (await res.json()) as DeviceDetail;
+        if (!cancelled) setDevice(data);
+      } catch (err: any) {
+        console.error('Error loading device details', err);
+        if (!cancelled) {
+          setError(
+            err instanceof Error
+              ? err.message
+              : 'Netzwerkfehler beim Laden der Gerätedaten.',
+          );
+        }
+      } finally {
+        if (!cancelled) setLoading(false);
+      }
+    }
+
+    loadDevice();
+    return () => {
+      cancelled = true;
+    };
+  }, [open, inventoryNumber]);
+
+  const handleClose = () => onClose();
+
+  return (
+    <Modal
+      open={open}
+      onClose={handleClose}
+      title={
+        device
+          ? `Gerätedetails: ${device.name}`
+          : 'Gerätedaten werden geladen …'
+      }
+      icon={<BookOpenIcon className="size-6" />}
+      tone="info"
+      variant="centered"
+      size="xl"
+      primaryAction={{
+        label: 'Schließen',
+        onClick: handleClose,
+        variant: 'primary',
+      }}
+      headerExtras={
+        device && (
+          <div className="sm:hidden">
+            <Tabs
+              tabs={[
+                { id: 'details', label: 'Details' },
+                { id: 'history', label: 'Änderungsverlauf' },
+              ]}
+              value={activeTab}
+              onChange={(id) => setActiveTab(id as 'details' | 'history')}
+              ariaLabel="Ansicht wählen"
+            />
+          </div>
+        )
+      }
+      sidebar={
+        device ? (
+          <div className="hidden w-full h-full sm:flex sm:flex-col sm:gap-4">
+            {/* QR-Code oben, nicht scrollend */}
+            <div className="rounded-lg border border-gray-800 bg-gray-900/70 px-4 py-3 shadow-sm">
+              <div className="mt-2 flex justify-center">
+                <div className="rounded-md bg-black/80 p-2">
+                  <DeviceQrCode inventoryNumber={device.inventoryNumber} />
+                </div>
+              </div>
+              <p className="mt-2 text-center text-[12px] text-gray-500">
+                #{device.inventoryNumber}
+              </p>
+            </div>
+
+            <div className="border-t border-gray-800 dark:border-white/10 mx-1" />
+
+            {/* Änderungsverlauf: nimmt den Rest der Höhe ein und scrollt intern */}
+            <div className="flex-1 min-h-0 overflow-hidden">
+              <DeviceHistorySidebar
+                key={device.updatedAt}
+                inventoryNumber={device.inventoryNumber}
+                asSidebar
+              />
+            </div>
+          </div>
+        ) : undefined
+      }
+    >
+      {loading && (
+        <p className="text-sm text-gray-500 dark:text-gray-400">
+          Gerätedaten werden geladen …
+        </p>
+      )}
+
+      {error && (
+        <p className="text-sm text-red-600 dark:text-red-400">
+          {error}
+        </p>
+      )}
+
+      {!loading && !error && device && (
+        <>
+          {/* Mobile-Inhalt (Tabs steuern Ansicht) */}
+          <div className="sm:hidden pr-2">
+            {activeTab === 'details' ? (
+              <DeviceDetailsGrid device={device} />
+            ) : (
+              <DeviceHistorySidebar
+                key={device.updatedAt + '-mobile'}
+                inventoryNumber={device.inventoryNumber}
+              />
+            )}
+          </div>
+
+          {/* Desktop-Inhalt links: nur Details, Verlauf rechts in sidebar */}
+          <div className="hidden sm:block pr-2">
+            <DeviceDetailsGrid device={device} />
+          </div>
+        </>
+      )}
+    </Modal>
+  );
+}
\ No newline at end of file
diff --git a/app/(app)/devices/DeviceEditModal.tsx b/app/(app)/devices/DeviceEditModal.tsx
index 25f54fe..12d764f 100644
--- a/app/(app)/devices/DeviceEditModal.tsx
+++ b/app/(app)/devices/DeviceEditModal.tsx
@@ -1,12 +1,19 @@
-// app/(app)/devices/DeviceEditModal.tsx
 'use client';
 
-import { useCallback, useEffect, useState, ChangeEvent, Dispatch, SetStateAction } from 'react';
+import {
+  useCallback,
+  useEffect,
+  useState,
+  ChangeEvent,
+  Dispatch,
+  SetStateAction,
+} from 'react';
 import Modal from '@/components/ui/Modal';
-import { PencilIcon } from '@heroicons/react/24/outline';
+import { PencilIcon, CheckCircleIcon } from '@heroicons/react/24/solid';
 import DeviceHistorySidebar from './DeviceHistorySidebar';
 import TagMultiCombobox, { TagOption } from '@/components/ui/TagMultiCombobox';
-import type { DeviceDetail } from './page'; // Typ aus page.tsx (siehe unten)
+import Button from '@/components/ui/Button';
+import type { DeviceDetail } from './page';
 
 type DeviceEditModalProps = {
   open: boolean;
@@ -29,25 +36,23 @@ export default function DeviceEditModal({
   const [editLoading, setEditLoading] = useState(false);
   const [editError, setEditError] = useState<string | null>(null);
   const [saveLoading, setSaveLoading] = useState(false);
+  const [justSaved, setJustSaved] = useState(false);
 
-  // Gerät laden, wenn Modal geöffnet wird
   useEffect(() => {
-    if (!open || !inventoryNumber) {
-      setEditDevice(null);
-      setEditError(null);
-      return;
-    }
+    if (!open || !inventoryNumber) return;
 
+    const inv = inventoryNumber;
     let cancelled = false;
 
-    async function loadDevice() {
-      setEditLoading(true);
-      setEditError(null);
-      setEditDevice(null);
+    setEditLoading(true);
+    setEditError(null);
+    setJustSaved(false);
+    setEditDevice(null);
 
+    async function loadDevice() {
       try {
         const res = await fetch(
-          `/api/devices/${encodeURIComponent(inventoryNumber)}`,
+          `/api/devices/${encodeURIComponent(inv)}`,
           {
             method: 'GET',
             headers: { 'Content-Type': 'application/json' },
@@ -59,7 +64,9 @@ export default function DeviceEditModal({
           if (res.status === 404) {
             throw new Error('Gerät wurde nicht gefunden.');
           }
-          throw new Error('Beim Laden der Gerätedaten ist ein Fehler aufgetreten.');
+          throw new Error(
+            'Beim Laden der Gerätedaten ist ein Fehler aufgetreten.',
+          );
         }
 
         const data = (await res.json()) as DeviceDetail;
@@ -70,7 +77,9 @@ export default function DeviceEditModal({
         console.error('Error loading device', err);
         if (!cancelled) {
           setEditError(
-            err instanceof Error ? err.message : 'Netzwerkfehler beim Laden der Gerätedaten.',
+            err instanceof Error
+              ? err.message
+              : 'Netzwerkfehler beim Laden der Gerätedaten.',
           );
         }
       } finally {
@@ -137,16 +146,23 @@ export default function DeviceEditModal({
 
       const updated = (await res.json()) as DeviceDetail;
       setEditDevice(updated);
-      onSaved(updated); // Tabelle im Parent aktualisieren
+      onSaved(updated);
+
+      setJustSaved(true);
+      setTimeout(() => {
+        onClose();
+      }, 1000);
     } catch (err: any) {
       console.error('Error saving device', err);
       setEditError(
-        err instanceof Error ? err.message : 'Netzwerkfehler beim Speichern der Gerätedaten.',
+        err instanceof Error
+          ? err.message
+          : 'Netzwerkfehler beim Speichern der Gerätedaten.',
       );
     } finally {
       setSaveLoading(false);
     }
-  }, [editDevice, onSaved]);
+  }, [editDevice, onSaved, onClose]);
 
   const handleClose = () => {
     if (saveLoading) return;
@@ -163,22 +179,54 @@ export default function DeviceEditModal({
           : 'Gerätedaten werden geladen …'
       }
       icon={<PencilIcon className="size-6" />}
-      tone="info"
+      tone={justSaved ? 'success' : 'info'}
       variant="centered"
-      size="lg"
-      primaryAction={{
-        label: saveLoading ? 'Speichern …' : 'Speichern',
-        onClick: handleSave,
-        autoFocus: true,
-      }}
-      secondaryAction={{
-        label: 'Abbrechen',
-        variant: 'secondary',
-        onClick: handleClose,
-      }}
+      size="xl"
+      footer={
+        <div className="px-4 py-3 sm:px-6">
+          <div className="flex flex-col gap-3 sm:flex-row-reverse">
+            <Button
+              type="button"
+              onClick={handleSave}
+              size="lg"
+              variant="primary"
+              tone={justSaved ? 'emerald' : 'indigo'}
+              disabled={saveLoading}
+              className="w-full sm:flex-1"
+              icon={
+                justSaved ? (
+                  <CheckCircleIcon
+                    aria-hidden="true"
+                    className="-ml-0.5 size-5"
+                  />
+                ) : undefined
+              }
+              iconPosition="leading"
+            >
+              {saveLoading
+                ? 'Speichern …'
+                : justSaved
+                  ? 'Gespeichert'
+                  : 'Speichern'}
+            </Button>
+
+            <Button
+              type="button"
+              onClick={handleClose}
+              size="lg"
+              variant="secondary"
+              tone="gray"
+              className="w-full sm:flex-1"
+            >
+              Abbrechen
+            </Button>
+          </div>
+        </div>
+      }
       sidebar={
         editDevice ? (
           <DeviceHistorySidebar
+            key={editDevice.updatedAt}
             inventoryNumber={editDevice.inventoryNumber}
             asSidebar
           />
@@ -192,11 +240,13 @@ export default function DeviceEditModal({
       )}
 
       {editError && (
-        <p className="text-sm text-red-600 dark:text-red-400">{editError}</p>
+        <p className="text-sm text-red-600 dark:text-red-400">
+          {editError}
+        </p>
       )}
 
       {!editLoading && !editError && editDevice && (
-        <div className="mt-3 grid grid-cols-1 gap-4 text-sm sm:grid-cols-2">
+        <div className="pr-2 mt-3 grid grid-cols-1 gap-4 text-sm sm:grid-cols-2">
           {/* Inventarnummer */}
           <div>
             <p className="text-xs font-semibold uppercase tracking-wide text-gray-400">
@@ -307,12 +357,10 @@ export default function DeviceEditModal({
               onChange={(next) => {
                 const names = next.map((t) => t.name);
 
-                // in editDevice speichern
                 setEditDevice((prev) =>
                   prev ? ({ ...prev, tags: names } as DeviceDetail) : prev,
                 );
 
-                // allTags im Parent erweitern
                 setAllTags((prev) => {
                   const map = new Map(prev.map((t) => [t.name.toLowerCase(), t]));
                   for (const t of next) {
@@ -365,6 +413,7 @@ export default function DeviceEditModal({
             />
           </div>
 
+          {/* Zugangsdaten */}
           <div>
             <p className="text-xs font-semibold uppercase tracking-wide text-gray-400">
               Benutzername
diff --git a/app/(app)/devices/DeviceHistorySidebar.tsx b/app/(app)/devices/DeviceHistorySidebar.tsx
index 08edc89..e0620bb 100644
--- a/app/(app)/devices/DeviceHistorySidebar.tsx
+++ b/app/(app)/devices/DeviceHistorySidebar.tsx
@@ -6,6 +6,8 @@ import Feed, {
   FeedItem,
   FeedChange,
 } from '@/components/ui/Feed';
+import clsx from 'clsx';
+
 
 type Props = {
   inventoryNumber: string;
@@ -35,33 +37,33 @@ function formatDateTime(iso: string) {
 function mapFieldLabel(field: string): string {
   switch (field) {
     case 'name':
-      return 'die Bezeichnung';
+      return 'Bezeichnung';
     case 'manufacturer':
-      return 'den Hersteller';
+      return 'Hersteller';
     case 'model':
-      return 'das Modell';
+      return 'Modell';
     case 'serialNumber':
-      return 'die Seriennummer';
+      return 'Seriennummer';
     case 'productNumber':
-      return 'die Produktnummer';
+      return 'Produktnummer';
     case 'comment':
-      return 'den Kommentar';
+      return 'Kommentar';
     case 'ipv4Address':
-      return 'die IPv4-Adresse';
+      return 'IPv4-Adresse';
     case 'ipv6Address':
-      return 'die IPv6-Adresse';
+      return 'IPv6-Adresse';
     case 'macAddress':
-      return 'die MAC-Adresse';
+      return 'MAC-Adresse';
     case 'username':
-      return 'den Benutzernamen';
+      return 'Benutzernamen';
     case 'passwordHash':
-      return 'das Passwort';
+      return 'Passwort';
     case 'group':
-      return 'die Gruppe';
+      return 'Gruppe';
     case 'location':
-      return 'den Standort';
+      return 'Standort';
     case 'tags':
-      return 'die Tags';
+      return 'Tags';
     default:
       return field;
   }
@@ -81,7 +83,6 @@ export default function DeviceHistorySidebar({
     async function loadHistory() {
       setLoading(true);
       setError(null);
-
       try {
         const res = await fetch(
           `/api/devices/${encodeURIComponent(inventoryNumber)}/history`,
@@ -123,12 +124,17 @@ export default function DeviceHistorySidebar({
           }
 
           let comment = '';
+          let commentKind: 'created' | 'deleted' | 'generic' = 'generic';
+
           if (entry.changeType === 'CREATED') {
-            comment = 'Gerät angelegt.';
+            comment = 'hat das Gerät angelegt.';
+            commentKind = 'created';
           } else if (entry.changeType === 'DELETED') {
-            comment = 'Gerät gelöscht.';
+            comment = 'hat das Gerät gelöscht.';
+            commentKind = 'deleted';
           } else {
-            comment = 'Gerät geändert.';
+            comment = 'hat das Gerät geändert.';
+            commentKind = 'generic';
           }
 
           return {
@@ -137,6 +143,7 @@ export default function DeviceHistorySidebar({
             person,
             date,
             comment,
+            commentKind,
           };
         });
 
@@ -161,13 +168,14 @@ export default function DeviceHistorySidebar({
   }, [inventoryNumber]);
 
   // Root-Tag & Klassen abhängig vom Einsatz
+  
   const Root: ElementType = asSidebar ? 'div' : 'aside';
-  const rootClasses = asSidebar
-    ? 'flex h-full flex-col text-sm'
-    : 'flex h-full flex-col border-l border-gray-200 px-4 py-4 text-sm dark:border-white/10';
-
+  const rootClassName = asSidebar
+    ? 'flex h-full min-h-0 flex-col'
+    : undefined;
+  
   return (
-    <Root className={rootClasses}>
+    <Root className={rootClassName}>
       <h2 className="text-sm font-semibold text-gray-900 dark:text-gray-100">
         Änderungsverlauf
       </h2>
@@ -185,10 +193,15 @@ export default function DeviceHistorySidebar({
       )}
 
       {!loading && !error && (
-        <div className="mt-3 flex-1 min-h-0">
-          <Feed items={items} className="h-full" />
+        <div
+          className={clsx(
+            'mt-3',
+            asSidebar && 'min-h-0 flex-1 overflow-y-auto pr-1'
+          )}
+        >
+          <Feed items={items} />
         </div>
       )}
     </Root>
   );
-}
+}
\ No newline at end of file
diff --git a/app/(app)/devices/page.tsx b/app/(app)/devices/page.tsx
index 2ecf2d2..04f2f93 100644
--- a/app/(app)/devices/page.tsx
+++ b/app/(app)/devices/page.tsx
@@ -10,31 +10,31 @@ import {
   BookOpenIcon,
   PencilIcon,
   TrashIcon,
+  PlusIcon
 } from '@heroicons/react/24/outline';
 import { getSocket } from '@/lib/socketClient';
 import type { TagOption } from '@/components/ui/TagMultiCombobox';
 import DeviceEditModal from './DeviceEditModal';
+import DeviceDetailModal from './DeviceDetailModal';
+import DeviceCreateModal from './DeviceCreateModal';
 
 export type DeviceRow = {
   inventoryNumber: string;
-
   name: string;
   manufacturer: string;
   model: string;
-  serialNumber?: string | null;
-  productNumber?: string | null;
-  comment?: string | null;
-
-  ipv4Address?: string | null;
-  ipv6Address?: string | null;
-  macAddress?: string | null;
-  username?: string | null;
-  passwordHash?: string | null;
-
-  group?: string | null;
-  location?: string | null;
-  tags?: string[] | null;
-
+  serialNumber: string | null;
+  productNumber: string | null;
+  comment: string | null;
+  group: string | null;
+  location: string | null;
+  ipv4Address: string | null;
+  ipv6Address: string | null;
+  macAddress: string | null;
+  username: string | null;
+  passwordHash: string | null;
+  tags: string[];
+  createdAt: string;
   updatedAt: string;
 };
 
@@ -52,17 +52,15 @@ function formatDate(iso: string) {
 const columns: TableColumn<DeviceRow>[] = [
   {
     key: 'inventoryNumber',
-    header: 'Inventar-Nr.',
+    header: 'Nr.',
     sortable: true,
     canHide: false,
-    headerClassName: 'min-w-32',
   },
   {
     key: 'name',
     header: 'Bezeichnung',
     sortable: true,
     canHide: true,
-    headerClassName: 'min-w-48',
     cellClassName: 'font-medium text-gray-900 dark:text-white',
   },
   {
@@ -132,9 +130,13 @@ export default function DevicesPage() {
   const [listError, setListError] = useState<string | null>(null);
 
   // welches Gerät ist gerade im Edit-Modal geöffnet?
-  const [editInventoryNumber, setEditInventoryNumber] = useState<string | null>(
-    null,
-  );
+  const [editInventoryNumber, setEditInventoryNumber] = useState<string | null>(null);
+
+  // welches Gerät ist im Detail-Modal geöffnet?
+  const [detailInventoryNumber, setDetailInventoryNumber] = useState<string | null>(null);
+  
+  // Create-Modal
+  const [createOpen, setCreateOpen] = useState(false);
 
   // Alle bekannten Tags (kannst du später auch aus eigener /api/tags laden)
   const [allTags, setAllTags] = useState<TagOption[]>([]);
@@ -238,6 +240,23 @@ export default function DevicesPage() {
     setEditInventoryNumber(null);
   }, []);
 
+  const handleDetails = useCallback((inventoryNumber: string) => {
+    setDetailInventoryNumber(inventoryNumber);
+  }, []);
+
+  const closeDetailModal = useCallback(() => {
+    setDetailInventoryNumber(null);
+  }, []);
+
+  const openCreateModal = useCallback(() => {
+    setCreateOpen(true);
+  }, []);
+
+  const closeCreateModal = useCallback(() => {
+    setCreateOpen(false);
+  }, []);
+
+
   /* ───────── Render ───────── */
 
   return (
@@ -253,12 +272,17 @@ export default function DevicesPage() {
           </p>
         </div>
 
-        <button
-          type="button"
-          className="inline-flex items-center rounded-md bg-indigo-600 px-3.5 py-2.5 text-sm font-semibold text-white shadow-xs hover:bg-indigo-500 focus-visible:outline-2 focus-visible:outline-offset-2 focus-visible:outline-indigo-600 dark:bg-indigo-500 dark:hover:bg-indigo-400 dark:focus-visible:outline-indigo-500"
+        <Button
+          variant="soft"
+          tone="indigo"
+          size="md"
+          icon={<PlusIcon className="size-5" />}
+          aria-label="Neues Gerät anlegen"
+          onClick={openCreateModal}
+          title='Neues Gerät anlegen'
         >
           Neues Gerät anlegen
-        </button>
+        </Button>
       </div>
 
       {listLoading && (
@@ -291,7 +315,7 @@ export default function DevicesPage() {
                   size="md"
                   icon={<BookOpenIcon className="size-5" />}
                   aria-label={`Details zu ${row.inventoryNumber}`}
-                  onClick={() => console.log('Details', row.inventoryNumber)}
+                  onClick={() => handleDetails(row.inventoryNumber)}
                 />
 
                 <Button
@@ -326,8 +350,7 @@ export default function DevicesPage() {
                         {
                           label: 'Details',
                           icon: <BookOpenIcon className="size-4" />,
-                          onClick: () =>
-                            console.log('Details', row.inventoryNumber),
+                          onClick: () => handleDetails(row.inventoryNumber),
                         },
                         {
                           label: 'Bearbeiten',
@@ -368,6 +391,28 @@ export default function DevicesPage() {
           );
         }}
       />
+
+      <DeviceCreateModal
+        open={createOpen}
+        onClose={closeCreateModal}
+        allTags={allTags}
+        setAllTags={setAllTags}
+        onCreated={(created) => {
+          setDevices((prev) => {
+            // falls Live-Update denselben Eintrag schon gebracht hat
+            if (prev.some((d) => d.inventoryNumber === created.inventoryNumber)) {
+              return prev;
+            }
+            return [...prev, created];
+          });
+        }}
+      />
+
+      <DeviceDetailModal
+        open={detailInventoryNumber !== null}
+        inventoryNumber={detailInventoryNumber}
+        onClose={closeDetailModal}
+      />
     </>
   );
 }
diff --git a/app/(app)/layout.tsx b/app/(app)/layout.tsx
index a2641a9..a29ecd1 100644
--- a/app/(app)/layout.tsx
+++ b/app/(app)/layout.tsx
@@ -28,9 +28,11 @@ import {
   XMarkIcon,
 } from '@heroicons/react/24/outline';
 import { ChevronDownIcon, MagnifyingGlassIcon } from '@heroicons/react/20/solid';
-import { usePathname } from 'next/navigation';
+import { usePathname, useRouter } from 'next/navigation';
 import { useSession, signOut } from 'next-auth/react';
 import { Skeleton } from '@/components/ui/Skeleton';
+import ScanModal from '@/components/ScanModal';
+import DeviceDetailModal from './devices/DeviceDetailModal';
 
 const navigation = [
   { name: 'Dashboard', href: '/dashboard', icon: HomeIcon },
@@ -143,7 +145,11 @@ function UserMenu({ displayName, avatarInitial, avatarColorClass }: UserMenuProp
 
 export default function AppLayout({ children }: { children: ReactNode }) {
   const [sidebarOpen, setSidebarOpen] = useState(false);
+  const [scanOpen, setScanOpen] = useState(false);
+  const [detailOpen, setDetailOpen] = useState(false);
+  const [detailInventoryNumber, setDetailInventoryNumber] = useState<string | null>(null);
   const pathname = usePathname();
+  const router = useRouter();
   const { data: session, status } = useSession();
 
   const rawName =
@@ -154,6 +160,43 @@ export default function AppLayout({ children }: { children: ReactNode }) {
   const displayName = rawName;
   const avatarInitial = getInitial(rawName);
   const avatarColorClass = getAvatarColor(rawName);
+  
+  const handleScanResult = (code: string) => {
+    const trimmed = code.trim();
+    if (!trimmed) return;
+
+    // 1) Versuch: QR-Code ist eine URL
+    try {
+      const url = new URL(trimmed);
+
+      const isSameOrigin =
+        typeof window !== 'undefined' &&
+        url.origin === window.location.origin;
+
+      if (isSameOrigin) {
+        // Beispiel: /devices/123456
+        const parts = url.pathname.split('/').filter(Boolean);
+        const idx = parts.indexOf('devices');
+
+        if (idx >= 0 && parts[idx + 1]) {
+          const inv = decodeURIComponent(parts[idx + 1]);
+          setDetailInventoryNumber(inv);
+          setDetailOpen(true);
+          return;
+        }
+      }
+
+      // Andere Domain → im Browser extern öffnen
+      window.open(trimmed, '_blank', 'noopener,noreferrer');
+      return;
+    } catch {
+      // Kein gültiger URL → weiter unten behandeln
+    }
+
+    // 2) Kein URL → pure Inventarnummer in der Webapp
+    setDetailInventoryNumber(trimmed);
+    setDetailOpen(true);
+  };
 
   return (
     <div className="min-h-screen bg-white dark:bg-gray-900">
@@ -347,17 +390,24 @@ export default function AppLayout({ children }: { children: ReactNode }) {
 
           <div className="flex flex-1 items-center gap-x-4 self-stretch lg:gap-x-6">
             {/* Suche */}
-            <form action="#" method="GET" className="grid flex-1 grid-cols-1">
-                <input
-                name="search"
-                placeholder="Suchen..."
-                aria-label="Suchen..."
-                className="col-start-1 row-start-1 block size-full bg-white pl-8 text-base text-gray-900 outline-hidden placeholder:text-gray-400 sm:text-sm/6 dark:bg-gray-900 dark:text-white dark:placeholder:text-gray-500"
-                />
+            <form
+              action="#"
+              method="GET"
+              className="grid flex-1 grid-cols-1"
+            >
+              <div className="relative">
                 <MagnifyingGlassIcon
-                aria-hidden="true"
-                className="pointer-events-none col-start-1 row-start-1 size-5 self-center text-gray-400"
+                  aria-hidden="true"
+                  className="pointer-events-none absolute left-3 top-1/2 size-5 -translate-y-1/2 text-gray-400 dark:text-gray-500"
                 />
+                <input
+                  type="search"
+                  name="search"
+                  placeholder="Suchen…"
+                  aria-label="Suchen"
+                  className="block w-full rounded-xl border-0 bg-gray-50 py-1.5 pl-10 pr-3 text-sm text-gray-900 shadow-xs ring-1 ring-inset ring-gray-300 placeholder:text-gray-400 focus:ring-2 focus:ring-indigo-500 focus:outline-none dark:bg-gray-800 dark:text-white dark:ring-gray-700 dark:placeholder:text-gray-500"
+                />
+              </div>
             </form>
 
             <div className="flex items-center gap-x-4 lg:gap-x-6">
@@ -369,8 +419,9 @@ export default function AppLayout({ children }: { children: ReactNode }) {
 
                 {/* Kamera-Button – nur mobil */}
                 <button
-                type="button"
-                className="-m-2.5 p-2.5 text-gray-400 hover:text-gray-500 dark:hover:text-white lg:hidden"
+                  type="button"
+                  className="-m-2.5 p-2.5 text-gray-400 hover:text-gray-500 dark:hover:text-white lg:hidden"
+                  onClick={() => setScanOpen(true)}
                 >
                 <span className="sr-only">Gerät mit Kamera erfassen</span>
                 <CameraIcon aria-hidden="true" className="size-5" />
@@ -420,6 +471,18 @@ export default function AppLayout({ children }: { children: ReactNode }) {
         <main className="py-10">
           <div className="px-4 sm:px-6 lg:px-8">{children}</div>
         </main>
+
+        <ScanModal
+          open={scanOpen}
+          onClose={() => setScanOpen(false)}
+          onResult={handleScanResult}
+        />
+        
+        <DeviceDetailModal
+          open={detailOpen}
+          inventoryNumber={detailInventoryNumber}
+          onClose={() => setDetailOpen(false)}
+        />
       </div>
     </div>
   );
diff --git a/app/api/devices/[id]/history/route.ts b/app/api/devices/[id]/history/route.ts
index abc001a..2a149bd 100644
--- a/app/api/devices/[id]/history/route.ts
+++ b/app/api/devices/[id]/history/route.ts
@@ -3,59 +3,63 @@ import { NextResponse } from 'next/server';
 import { prisma } from '@/lib/prisma';
 
 type RouteParams = { id: string };
-// ⬇️ wie bei /api/devices/[id]
 type RouteContext = { params: Promise<RouteParams> };
 
-export async function GET(
-  _req: Request,
-  ctx: RouteContext,
-) {
-  // params-Promise auflösen
+export async function GET(_req: Request, ctx: RouteContext) {
   const { id } = await ctx.params;
-  const inventoryNumber = decodeURIComponent(id);
+
+  if (!id) {
+    return NextResponse.json({ error: 'MISSING_ID' }, { status: 400 });
+  }
 
   try {
     const history = await prisma.deviceHistory.findMany({
-      where: { deviceId: inventoryNumber },
-      include: { changedBy: true },
+      where: { deviceId: id },
       orderBy: { changedAt: 'desc' },
+      include: {
+        changedBy: true, // 👈 User-Relation laden
+      },
     });
 
-    const payload = history.map((entry) => {
+    const result = history.map((entry) => {
+      // 👇 hier baust du den Anzeigenamen
+      const changedByName =
+        entry.changedBy?.name ??
+        entry.changedBy?.username ??
+        entry.changedBy?.email ??
+        null;
+
+      // snapshot.changes aus dem JSON holen (bei CREATED leer)
+      let changes: {
+        field: string;
+        from: string | null;
+        to: string | null;
+      }[] = [];
+
       const snapshot = entry.snapshot as any;
-
-      const rawChanges: any[] = Array.isArray(snapshot?.changes)
-        ? snapshot.changes
-        : [];
-
-      const changes = rawChanges.map((c) => ({
-        field: String(c.field),
-        from:
-          c.before === null || c.before === undefined
-            ? null
-            : String(c.before),
-        to:
-          c.after === null || c.after === undefined
-            ? null
-            : String(c.after),
-      }));
+      if (snapshot && Array.isArray(snapshot.changes)) {
+        changes = snapshot.changes.map((c: any) => ({
+          field: String(c.field),
+          from: c.before ?? null,
+          to: c.after ?? null,
+        }));
+      }
 
       return {
         id: entry.id,
-        changeType: entry.changeType, // 'CREATED' | 'UPDATED' | 'DELETED'
+        changeType: entry.changeType,
         changedAt: entry.changedAt.toISOString(),
-        changedBy:
-          entry.changedBy?.name ??
-          entry.changedBy?.username ??
-          entry.changedBy?.email ??
-          null,
+        changedBy: changedByName,   // 👈 passt zu deinem ApiHistoryEntry
         changes,
       };
     });
 
-    return NextResponse.json(payload);
+    return NextResponse.json(result);
   } catch (err) {
     console.error('[GET /api/devices/[id]/history]', err);
-    return NextResponse.json({ error: 'INTERNAL_ERROR' }, { status: 500 });
+    return NextResponse.json(
+      { error: 'INTERNAL_ERROR' },
+      { status: 500 },
+    );
   }
 }
diff --git a/app/api/devices/[id]/route.ts b/app/api/devices/[id]/route.ts
index 3a04367..8bf360f 100644
--- a/app/api/devices/[id]/route.ts
+++ b/app/api/devices/[id]/route.ts
@@ -61,29 +61,265 @@ export async function GET(
   }
 }
 
+export async function POST(req: Request) {
+  try {
+    const body = await req.json();
+
+    const {
+      inventoryNumber,
+      name,
+      manufacturer,
+      model,
+      serialNumber,
+      productNumber,
+      comment,
+      group,      // Name der Gruppe (string)
+      location,   // Name des Standorts (string)
+      ipv4Address,
+      ipv6Address,
+      macAddress,
+      username,
+      passwordHash,
+      tags,       // string[]
+    } = body;
+
+    if (!inventoryNumber || !name) {
+      return NextResponse.json(
+        { error: 'inventoryNumber und name sind Pflichtfelder.' },
+        { status: 400 },
+      );
+    }
+
+    // prüfen, ob Inventar-Nr. schon existiert
+    const existing = await prisma.device.findUnique({
+      where: { inventoryNumber },
+    });
+    if (existing) {
+      return NextResponse.json(
+        { error: 'Gerät mit dieser Inventar-Nr. existiert bereits.' },
+        { status: 409 },
+      );
+    }
+
+    // 🔹 aktuell eingeloggten User ermitteln
+    const userId = await getCurrentUserId();
+
+    // 🔹 nur verknüpfen, wenn der User wirklich in der DB existiert
+    let canConnectUser = false;
+    if (userId) {
+      const user = await prisma.user.findUnique({
+        where: { id: userId },
+        select: { id: true },
+      });
+      if (user) {
+        canConnectUser = true;
+      } else {
+        console.warn(
+          `[POST /api/devices] User mit id=${userId} nicht gefunden – createdBy/changedBy werden nicht gesetzt.`,
+        );
+      }
+    }
+
+    // ✅ Gruppe nach Name auflösen / anlegen
+    let groupId: string | null = null;
+    if (group && typeof group === 'string' && group.trim() !== '') {
+      const grp = await prisma.deviceGroup.upsert({
+        where: { name: group.trim() },
+        update: {},
+        create: { name: group.trim() },
+      });
+      groupId = grp.id;
+    }
+
+    // ✅ Location nach Name auflösen / anlegen
+    let locationId: string | null = null;
+    if (location && typeof location === 'string' && location.trim() !== '') {
+      const loc = await prisma.location.upsert({
+        where: { name: location.trim() },
+        update: {},
+        create: { name: location.trim() },
+      });
+      locationId = loc.id;
+    }
+
+    // ✅ Tag-Namen vorbereiten
+    const tagNames: string[] = Array.isArray(tags)
+      ? tags
+          .map((t: unknown) => String(t).trim())
+          .filter((t) => t.length > 0)
+      : [];
+
+    // ✅ Device anlegen (mit createdBy & Tags)
+    const created = await prisma.device.create({
+      data: {
+        inventoryNumber,
+        name,
+        manufacturer,
+        model,
+        serialNumber: serialNumber ?? null,
+        productNumber: productNumber ?? null,
+        comment: comment ?? null,
+        ipv4Address: ipv4Address ?? null,
+        ipv6Address: ipv6Address ?? null,
+        macAddress: macAddress ?? null,
+        username: username ?? null,
+        passwordHash: passwordHash ?? null,
+        groupId,
+        locationId,
+        // User, der das Gerät angelegt hat
+        ...(canConnectUser && userId
+          ? {
+              createdBy: {
+                connect: { id: userId },
+              },
+            }
+          : {}),
+        // Tags Many-to-Many
+        ...(tagNames.length
+          ? {
+              tags: {
+                connectOrCreate: tagNames.map((name) => ({
+                  where: { name },
+                  create: { name },
+                })),
+              },
+            }
+          : {}),
+      },
+      include: {
+        group: true,
+        location: true,
+        tags: true,
+        createdBy: true,
+      },
+    });
+
+    // 🔹 History-Eintrag "CREATED" mit changedById
+    const snapshot: Prisma.JsonObject = {
+      before: null,
+      after: {
+        inventoryNumber: created.inventoryNumber,
+        name: created.name,
+        manufacturer: created.manufacturer,
+        model: created.model,
+        serialNumber: created.serialNumber,
+        productNumber: created.productNumber,
+        comment: created.comment,
+        ipv4Address: created.ipv4Address,
+        ipv6Address: created.ipv6Address,
+        macAddress: created.macAddress,
+        username: created.username,
+        passwordHash: created.passwordHash,
+        group: created.group?.name ?? null,
+        location: created.location?.name ?? null,
+        tags: created.tags.map((t) => t.name),
+        createdAt: created.createdAt.toISOString(),
+        updatedAt: created.updatedAt.toISOString(),
+      },
+      changes: [],
+    };
+
+    await prisma.deviceHistory.create({
+      data: {
+        deviceId: created.inventoryNumber,
+        changeType: 'CREATED',
+        snapshot,
+        changedById: canConnectUser && userId ? userId : null,
+      },
+    });
+
+    // 🔊 optional: Socket.IO-Broadcast für Live-Listen
+    const io = (global as any).devicesIo as IOServer | undefined;
+    if (io) {
+      io.emit('device:created', {
+        inventoryNumber: created.inventoryNumber,
+        name: created.name,
+        manufacturer: created.manufacturer,
+        model: created.model,
+        serialNumber: created.serialNumber,
+        productNumber: created.productNumber,
+        comment: created.comment,
+        ipv4Address: created.ipv4Address,
+        ipv6Address: created.ipv6Address,
+        macAddress: created.macAddress,
+        username: created.username,
+        group: created.group?.name ?? null,
+        location: created.location?.name ?? null,
+        tags: created.tags.map((t) => t.name),
+        updatedAt: created.updatedAt.toISOString(),
+      });
+    }
+
+    // Antwort wie bei GET /api/devices
+    return NextResponse.json(
+      {
+        inventoryNumber: created.inventoryNumber,
+        name: created.name,
+        manufacturer: created.manufacturer,
+        model: created.model,
+        serialNumber: created.serialNumber,
+        productNumber: created.productNumber,
+        comment: created.comment,
+        ipv4Address: created.ipv4Address,
+        ipv6Address: created.ipv6Address,
+        macAddress: created.macAddress,
+        username: created.username,
+        passwordHash: created.passwordHash,
+        group: created.group?.name ?? null,
+        location: created.location?.name ?? null,
+        tags: created.tags.map((t) => t.name),
+        updatedAt: created.updatedAt.toISOString(),
+      },
+      { status: 201 },
+    );
+  } catch (err) {
+    console.error('Error in POST /api/devices', err);
+    return NextResponse.json(
+      { error: 'Interner Serverfehler beim Anlegen des Geräts.' },
+      { status: 500 },
+    );
+  }
+}
 
 export async function PATCH(
   req: Request,
   ctx: RouteContext,
 ) {
   const { id } = await ctx.params;
-  const body = await req.json();
 
   if (!id) {
     return NextResponse.json({ error: 'MISSING_ID' }, { status: 400 });
   }
 
   try {
-    // ⬇️ hier jetzt die Request-Header durchreichen
+    const body = await req.json();
+
+    // aktuell eingeloggten User ermitteln
     const userId = await getCurrentUserId();
 
+    // nur verbinden, wenn der User in der DB existiert
+    let canConnectUpdatedBy = false;
+    if (userId) {
+      const user = await prisma.user.findUnique({
+        where: { id: userId },
+        select: { id: true },
+      });
+      if (user) {
+        canConnectUpdatedBy = true;
+      } else {
+        console.warn(
+          `[PATCH /api/devices/${id}] User mit id=${userId} nicht gefunden – updatedBy wird nicht gesetzt.`,
+        );
+      }
+    }
+
     // aktuelles Gerät inkl. Relations laden (für "before"-Snapshot)
     const existing = await prisma.device.findUnique({
       where: { inventoryNumber: id },
       include: {
         group: true,
         location: true,
-        tags: true, // 🔹 NEU
+        tags: true,
       },
     });
 
@@ -96,53 +332,18 @@ export async function PATCH(
       name: body.name,
       manufacturer: body.manufacturer,
       model: body.model,
-      serialNumber: body.serialNumber,
-      productNumber: body.productNumber,
-      comment: body.comment,
-      ipv4Address: body.ipv4Address,
-      ipv6Address: body.ipv6Address,
-      macAddress: body.macAddress,
-      username: body.username,
-      passwordHash: body.passwordHash,
+      serialNumber: body.serialNumber ?? null,
+      productNumber: body.productNumber ?? null,
+      comment: body.comment ?? null,
+      ipv4Address: body.ipv4Address ?? null,
+      ipv6Address: body.ipv6Address ?? null,
+      macAddress: body.macAddress ?? null,
+      username: body.username ?? null,
+      passwordHash: body.passwordHash ?? null,
     };
 
-    // Tags aus dem Body bereinigen
-    const incomingTags: string[] = Array.isArray(body.tags)
-      ? body.tags.map((t: unknown) => String(t).trim()).filter(Boolean)
-      : [];
-
-    // existierende Tag-Namen
-    const existingTagNames = existing.tags.map((t) => t.name);
-
-    // welche sollen entfernt werden?
-    const tagsToRemove = existingTagNames.filter(
-      (name) => !incomingTags.includes(name),
-    );
-
-    // welche sind neu hinzuzufügen?
-    const tagsToAdd = incomingTags.filter(
-      (name) => !existingTagNames.includes(name),
-    );
-
-    if (!data.tags) {
-      data.tags = {};
-    }
-
-    // Tags, die nicht mehr vorkommen → disconnect über name (weil @unique)
-    if (tagsToRemove.length > 0) {
-      (data.tags as any).disconnect = tagsToRemove.map((name) => ({ name }));
-    }
-
-    // neue Tags → connectOrCreate (Tag wird bei Bedarf angelegt)
-    if (tagsToAdd.length > 0) {
-      (data.tags as any).connectOrCreate = tagsToAdd.map((name) => ({
-        where: { name },
-        create: { name },
-      }));
-    }
-
-    // updatedBy setzen, wenn User da
-    if (userId) {
+    // updatedBy nur setzen, wenn User existiert
+    if (canConnectUpdatedBy && userId) {
       data.updatedBy = {
         connect: { id: userId },
       };
@@ -172,15 +373,15 @@ export async function PATCH(
       data.location = { disconnect: true };
     }
 
-        // Tags (Many-to-Many via Tag.name @unique)
+    // Tags (Many-to-Many via Tag.name @unique)
     if (Array.isArray(body.tags)) {
       const tagNames = (body.tags as string[])
         .map((t) => String(t).trim())
         .filter(Boolean);
 
       const beforeNames = existing.tags.map((t) => t.name.toLowerCase());
-
       const normalized = tagNames.map((n) => n.toLowerCase());
+
       const toConnect = tagNames.filter(
         (n) => !beforeNames.includes(n.toLowerCase()),
       );
@@ -189,12 +390,10 @@ export async function PATCH(
         .filter((n) => !normalized.includes(n.toLowerCase()));
 
       data.tags = {
-        // neue / fehlende Tags verknüpfen (und ggf. anlegen)
         connectOrCreate: toConnect.map((name) => ({
           where: { name },
           create: { name },
         })),
-        // nicht mehr vorhandene Tags trennen
         disconnect: toDisconnect.map((name) => ({ name })),
       };
     }
@@ -227,7 +426,6 @@ export async function PATCH(
 
     type TrackedField = (typeof trackedFields)[number];
 
-    // explizit JSON-kompatible Types (string | null)
     const changes: {
       field: TrackedField | 'group' | 'location' | 'tags';
       before: string | null;
@@ -281,8 +479,7 @@ export async function PATCH(
       });
     }
 
-
-    // Falls sich *gar nichts* geändert hat, kein History-Eintrag
+    // Falls sich gar nichts geändert hat, kein History-Eintrag
     if (changes.length > 0) {
       const snapshot: Prisma.JsonObject = {
         before: {
@@ -330,17 +527,18 @@ export async function PATCH(
         })),
       };
 
+      // 🔴 WICHTIG: changedById nur setzen, wenn der User wirklich existiert
       await prisma.deviceHistory.create({
         data: {
           deviceId: updated.inventoryNumber,
           changeType: 'UPDATED',
           snapshot,
-          changedById: userId ?? null,
+          changedById: canConnectUpdatedBy && userId ? userId : null,
         },
       });
     }
 
-    // 🔊 Socket.IO-Broadcast für echte Live-Updates
+    // 🔊 Socket.IO-Broadcast für Live-Updates
     const io = (global as any).devicesIo as IOServer | undefined;
     if (io) {
       io.emit('device:updated', {
@@ -361,7 +559,7 @@ export async function PATCH(
       });
     }
 
-    // Antwort an den Client (flattened)
+    // Antwort an den Client
     return NextResponse.json({
       inventoryNumber: updated.inventoryNumber,
       name: updated.name,
@@ -376,6 +574,7 @@ export async function PATCH(
       username: updated.username,
       group: updated.group?.name ?? null,
       location: updated.location?.name ?? null,
+      tags: updated.tags.map((t) => t.name),
       createdAt: updated.createdAt.toISOString(),
       updatedAt: updated.updatedAt.toISOString(),
     });
@@ -383,4 +582,4 @@ export async function PATCH(
     console.error('[PATCH /api/devices/[id]]', err);
     return NextResponse.json({ error: 'INTERNAL_ERROR' }, { status: 500 });
   }
-}
+}
\ No newline at end of file
diff --git a/app/api/devices/route.ts b/app/api/devices/route.ts
index fb594b9..e1b4e24 100644
--- a/app/api/devices/route.ts
+++ b/app/api/devices/route.ts
@@ -1,6 +1,9 @@
 // app/api/devices/route.ts
 import { NextResponse } from 'next/server';
 import { prisma } from '@/lib/prisma';
+import type { Prisma } from '@prisma/client';
+import { getCurrentUserId } from '@/lib/auth';
+import type { Server as IOServer } from 'socket.io';
 
 export async function GET() {
   try {
@@ -8,7 +11,7 @@ export async function GET() {
       include: {
         group: true,
         location: true,
-        tags: true, // 🔹 NEU
+        tags: true,
       },
     });
 
@@ -32,9 +35,232 @@ export async function GET() {
         updatedAt: d.updatedAt.toISOString(),
       })),
     );
-
   } catch (err) {
     console.error('[GET /api/devices]', err);
     return NextResponse.json({ error: 'INTERNAL_ERROR' }, { status: 500 });
   }
 }
+
+export async function POST(req: Request) {
+  try {
+    const body = await req.json();
+
+    const {
+      inventoryNumber,
+      name,
+      manufacturer,
+      model,
+      serialNumber,
+      productNumber,
+      comment,
+      group,
+      location,
+      ipv4Address,
+      ipv6Address,
+      macAddress,
+      username,
+      passwordHash,
+      tags,
+    } = body;
+
+    if (!inventoryNumber || !name) {
+      return NextResponse.json(
+        { error: 'inventoryNumber und name sind Pflichtfelder.' },
+        { status: 400 },
+      );
+    }
+
+    const existing = await prisma.device.findUnique({
+      where: { inventoryNumber },
+    });
+    if (existing) {
+      return NextResponse.json(
+        { error: 'Gerät mit dieser Inventar-Nr. existiert bereits.' },
+        { status: 409 },
+      );
+    }
+
+    // aktuell eingeloggten User ermitteln
+    const userId = await getCurrentUserId();
+    let canConnectUser = false;
+
+    if (userId) {
+      const user = await prisma.user.findUnique({
+        where: { id: userId },
+        select: { id: true },
+      });
+      if (user) {
+        canConnectUser = true;
+      } else {
+        console.warn(
+          `[POST /api/devices] User mit id=${userId} nicht gefunden – createdBy/changedBy werden nicht gesetzt.`,
+        );
+      }
+    }
+
+    // Gruppe / Standort (per Name) anlegen/finden
+    let groupId: string | null = null;
+    if (group && typeof group === 'string' && group.trim() !== '') {
+      const grp = await prisma.deviceGroup.upsert({
+        where: { name: group.trim() },
+        update: {},
+        create: { name: group.trim() },
+      });
+      groupId = grp.id;
+    }
+
+    let locationId: string | null = null;
+    if (location && typeof location === 'string' && location.trim() !== '') {
+      const loc = await prisma.location.upsert({
+        where: { name: location.trim() },
+        update: {},
+        create: { name: location.trim() },
+      });
+      locationId = loc.id;
+    }
+
+    const tagNames: string[] = Array.isArray(tags)
+      ? tags.map((t: unknown) => String(t).trim()).filter(Boolean)
+      : [];
+
+    const created = await prisma.device.create({
+      data: {
+        inventoryNumber,
+        name,
+        manufacturer,
+        model,
+        serialNumber: serialNumber ?? null,
+        productNumber: productNumber ?? null,
+        comment: comment ?? null,
+        ipv4Address: ipv4Address ?? null,
+        ipv6Address: ipv6Address ?? null,
+        macAddress: macAddress ?? null,
+        username: username ?? null,
+        passwordHash: passwordHash ?? null,
+
+        // ⬇️ Relation über group/location, nicht groupId/locationId
+        ...(groupId
+          ? {
+              group: {
+                connect: { id: groupId },
+              },
+            }
+          : {}),
+
+        ...(locationId
+          ? {
+              location: {
+                connect: { id: locationId },
+              },
+            }
+          : {}),
+
+        // User, der das Gerät angelegt hat
+        ...(canConnectUser && userId
+          ? { createdBy: { connect: { id: userId } } }
+          : {}),
+
+        // Tags Many-to-Many
+        ...(tagNames.length
+          ? {
+              tags: {
+                connectOrCreate: tagNames.map((name) => ({
+                  where: { name },
+                  create: { name },
+                })),
+              },
+            }
+          : {}),
+      },
+      include: {
+        group: true,
+        location: true,
+        tags: true,
+      },
+    });
+
+    // History-Eintrag "CREATED" mit changedById
+    const snapshot: Prisma.JsonObject = {
+      before: null,
+      after: {
+        inventoryNumber: created.inventoryNumber,
+        name: created.name,
+        manufacturer: created.manufacturer,
+        model: created.model,
+        serialNumber: created.serialNumber,
+        productNumber: created.productNumber,
+        comment: created.comment,
+        ipv4Address: created.ipv4Address,
+        ipv6Address: created.ipv6Address,
+        macAddress: created.macAddress,
+        username: created.username,
+        passwordHash: created.passwordHash,
+        group: created.group?.name ?? null,
+        location: created.location?.name ?? null,
+        tags: created.tags.map((t) => t.name),
+        createdAt: created.createdAt.toISOString(),
+        updatedAt: created.updatedAt.toISOString(),
+      },
+      changes: [],
+    };
+
+    await prisma.deviceHistory.create({
+      data: {
+        deviceId: created.inventoryNumber,
+        changeType: 'CREATED',
+        snapshot,
+        changedById: canConnectUser && userId ? userId : null,
+      },
+    });
+
+    // Socket-Event
+    const io = (global as any).devicesIo as IOServer | undefined;
+    if (io) {
+      io.emit('device:created', {
+        inventoryNumber: created.inventoryNumber,
+        name: created.name,
+        manufacturer: created.manufacturer,
+        model: created.model,
+        serialNumber: created.serialNumber,
+        productNumber: created.productNumber,
+        comment: created.comment,
+        ipv4Address: created.ipv4Address,
+        ipv6Address: created.ipv6Address,
+        macAddress: created.macAddress,
+        username: created.username,
+        group: created.group?.name ?? null,
+        location: created.location?.name ?? null,
+        tags: created.tags.map((t) => t.name),
+        updatedAt: created.updatedAt.toISOString(),
+      });
+    }
+
+    return NextResponse.json(
+      {
+        inventoryNumber: created.inventoryNumber,
+        name: created.name,
+        manufacturer: created.manufacturer,
+        model: created.model,
+        serialNumber: created.serialNumber,
+        productNumber: created.productNumber,
+        comment: created.comment,
+        ipv4Address: created.ipv4Address,
+        ipv6Address: created.ipv6Address,
+        macAddress: created.macAddress,
+        username: created.username,
+        passwordHash: created.passwordHash,
+        group: created.group?.name ?? null,
+        location: created.location?.name ?? null,
+        tags: created.tags.map((t) => t.name),
+        updatedAt: created.updatedAt.toISOString(),
+      },
+      { status: 201 },
+    );
+  } catch (err) {
+    console.error('[POST /api/devices]', err);
+    return NextResponse.json(
+      { error: 'Interner Serverfehler beim Anlegen des Geräts.' },
+      { status: 500 },
+    );
+  }
+}
\ No newline at end of file
diff --git a/components/DeviceQrCode.tsx b/components/DeviceQrCode.tsx
new file mode 100644
index 0000000..12308ff
--- /dev/null
+++ b/components/DeviceQrCode.tsx
@@ -0,0 +1,33 @@
+// components/DeviceQrCode.tsx
+'use client';
+
+import { QRCodeSVG } from 'qrcode.react';
+
+type DeviceQrCodeProps = {
+  inventoryNumber: string;
+  size?: number;
+};
+
+export function DeviceQrCode({ inventoryNumber, size = 180 }: DeviceQrCodeProps) {
+  const baseUrl = process.env.NEXT_PUBLIC_APP_URL ?? '';
+
+  // Immer vollständige URL für externe Scanner erzeugen
+  const qrValue = baseUrl
+    ? `${baseUrl.replace(/\/$/, '')}/devices/${encodeURIComponent(inventoryNumber)}`
+    : inventoryNumber;
+
+  return (
+    <div className="inline-flex flex-col items-center gap-2">
+      <QRCodeSVG
+        value={qrValue}
+        size={size}
+        level="M"              // Fehlertoleranz
+        includeMargin          // wichtiger weißer Rand (= Quiet Zone)
+        bgColor="#FFFFFF"
+        fgColor="#000000"
+      />
+      {/* Optional: zum Debuggen den Wert anzeigen */}
+      {/* <p className="text-[10px] text-gray-500 break-all text-center">{qrValue}</p> */}
+    </div>
+  );
+}
diff --git a/components/ScanModal.tsx b/components/ScanModal.tsx
new file mode 100644
index 0000000..b37a67e
--- /dev/null
+++ b/components/ScanModal.tsx
@@ -0,0 +1,145 @@
+// components/ScanModal.tsx
+'use client';
+
+import { useEffect, useRef, useState } from 'react';
+import Modal from '@/components/ui/Modal';
+import { CameraIcon } from '@heroicons/react/24/outline';
+import { BrowserMultiFormatReader, IScannerControls } from '@zxing/browser';
+
+type ScanModalProps = {
+  open: boolean;
+  onClose: () => void;
+  onResult: (code: string) => void;
+};
+
+export default function ScanModal({ open, onClose, onResult }: ScanModalProps) {
+  const videoRef = useRef<HTMLVideoElement | null>(null);
+  const [error, setError] = useState<string | null>(null);
+
+  useEffect(() => {
+    if (!open) return;
+
+    setError(null);
+
+    // Browser / Secure-Context Check
+    if (
+      typeof navigator === 'undefined' ||
+      !navigator.mediaDevices ||
+      typeof navigator.mediaDevices.getUserMedia !== 'function'
+    ) {
+      setError(
+        'Kamera wird in diesem Kontext nicht unterstützt. Bitte die Seite über HTTPS oder localhost aufrufen.',
+      );
+      return;
+    }
+
+    const codeReader = new BrowserMultiFormatReader();
+    let controls: IScannerControls | null = null;
+    let stopped = false;
+    let rafId: number | null = null;
+
+    const startScanner = () => {
+      // warten, bis das <video> da ist
+      if (!videoRef.current) {
+        rafId = requestAnimationFrame(startScanner);
+        return;
+      }
+
+      codeReader
+        .decodeFromConstraints(
+          {
+            audio: false,
+            video: {
+              facingMode: { ideal: 'environment' }, // Rückkamera bevorzugen
+            },
+          },
+          videoRef.current,
+          (result, err, _controls) => {
+            if (_controls && !controls) {
+              controls = _controls;
+            }
+
+            if (result && !stopped) {
+              stopped = true;
+              if (controls) controls.stop();
+              onResult(result.getText());
+              onClose();
+            }
+
+            if (err && err.name !== 'NotFoundException') {
+              console.warn('Scanner-Fehler:', err);
+            }
+          },
+        )
+        .catch((e) => {
+          console.error('Error starting camera', e);
+          setError(
+            'Kamera konnte nicht geöffnet werden. Bitte Berechtigungen prüfen oder einen anderen Browser verwenden.',
+          );
+        });
+    };
+
+    startScanner();
+
+    return () => {
+      stopped = true;
+
+      if (rafId !== null) {
+        cancelAnimationFrame(rafId);
+      }
+
+      if (controls) {
+        controls.stop();
+      }
+
+      // Stream hart stoppen, falls noch aktiv
+      if (videoRef.current && videoRef.current.srcObject instanceof MediaStream) {
+        videoRef.current.srcObject.getTracks().forEach((t) => t.stop());
+        videoRef.current.srcObject = null;
+      }
+
+      // ⚠️ KEIN codeReader.reset() mehr – macht bei dir Runtime-Fehler
+    };
+  }, [open, onClose, onResult]);
+
+  const handleClose = () => onClose();
+
+  return (
+    <Modal
+      open={open}
+      onClose={handleClose}
+      title="QR-Code scannen"
+      icon={<CameraIcon className="size-6" />}
+      tone="info"
+      variant="centered"
+      size="md"
+      primaryAction={{
+        label: 'Abbrechen',
+        onClick: handleClose,
+        variant: 'secondary',
+      }}
+    >
+      <div className="mt-4 space-y-3">
+        {error && (
+          <p className="text-sm text-red-600 dark:text-red-400">{error}</p>
+        )}
+
+        {!error && (
+          <p className="text-sm text-gray-500 dark:text-gray-400">
+            Richte deine Kamera auf den QR-Code. Sobald er erkannt wird, öffnet sich das Gerätedetail.
+          </p>
+        )}
+
+        <div className="mt-2 overflow-hidden rounded-lg border border-gray-200 bg-black dark:border-white/10">
+          <video
+            ref={videoRef}
+            autoPlay
+            playsInline
+            muted
+            className="block w-full h-80 object-contain"
+          />
+        </div>
+      </div>
+    </Modal>
+  );
+}
diff --git a/components/ui/Button.tsx b/components/ui/Button.tsx
index a069e16..175366c 100644
--- a/components/ui/Button.tsx
+++ b/components/ui/Button.tsx
@@ -5,7 +5,7 @@ import clsx from 'clsx';
 export type ButtonVariant = 'primary' | 'secondary' | 'soft';
 export type ButtonSize = 'xs' | 'sm' | 'md' | 'lg' | 'xl';
 export type ButtonShape = 'default' | 'pill' | 'circle';
-export type ButtonTone = 'indigo' | 'gray' | 'rose';
+export type ButtonTone = 'indigo' | 'gray' | 'rose' | 'emerald';
 
 export interface ButtonProps
   extends React.ButtonHTMLAttributes<HTMLButtonElement> {
@@ -38,6 +38,10 @@ const variantToneClasses: Record<ButtonVariant, Record<ButtonTone, string>> = {
       'bg-rose-600 text-white hover:bg-rose-500 ' +
       'focus-visible:outline-rose-600 ' +
       'dark:bg-rose-500 dark:text-white dark:hover:bg-rose-400 dark:shadow-none dark:focus-visible:outline-rose-500',
+    emerald:
+      'bg-emerald-600 text-white hover:bg-emerald-500 ' +
+      'focus-visible:outline-emerald-600 ' +
+      'dark:bg-emerald-500 dark:text-white dark:hover:bg-emerald-400 dark:shadow-none dark:focus-visible:outline-emerald-500',
   },
   secondary: {
     indigo:
@@ -52,6 +56,10 @@ const variantToneClasses: Record<ButtonVariant, Record<ButtonTone, string>> = {
       'bg-white text-rose-600 inset-ring inset-ring-rose-200 hover:bg-rose-50 ' +
       'focus-visible:outline-rose-600 ' +
       'dark:bg-white/10 dark:text-rose-300 dark:shadow-none dark:inset-ring-rose-500/40 dark:hover:bg-rose-500/10 dark:focus-visible:outline-rose-500',
+    emerald:
+      'bg-white text-emerald-600 inset-ring inset-ring-emerald-200 hover:bg-emerald-50 ' +
+      'focus-visible:outline-emerald-600 ' +
+      'dark:bg-white/10 dark:text-emerald-300 dark:shadow-none dark:inset-ring-emerald-500/40 dark:hover:bg-emerald-500/10 dark:focus-visible:outline-emerald-500',
   },
   soft: {
     indigo:
@@ -66,6 +74,10 @@ const variantToneClasses: Record<ButtonVariant, Record<ButtonTone, string>> = {
       'bg-rose-50 text-rose-600 hover:bg-rose-100 ' +
       'focus-visible:outline-rose-600 ' +
       'dark:bg-rose-500/20 dark:text-rose-300 dark:shadow-none dark:hover:bg-rose-500/30 dark:focus-visible:outline-rose-500',
+    emerald:
+      'bg-emerald-50 text-emerald-600 hover:bg-emerald-100 ' +
+      'focus-visible:outline-emerald-600 ' +
+      'dark:bg-emerald-500/20 dark:text-emerald-300 dark:shadow-none dark:hover:bg-emerald-500/30 dark:focus-visible:outline-emerald-500',
   },
 };
 
diff --git a/components/ui/Feed.tsx b/components/ui/Feed.tsx
index 7d48abf..45fe8f8 100644
--- a/components/ui/Feed.tsx
+++ b/components/ui/Feed.tsx
@@ -3,8 +3,10 @@
 
 import * as React from 'react';
 import {
-  ChatBubbleLeftEllipsisIcon,
   TagIcon,
+  PlusIcon,
+  TrashIcon,
+  PencilIcon
 } from '@heroicons/react/20/solid';
 import clsx from 'clsx';
 
@@ -39,6 +41,8 @@ export type FeedItem =
       imageUrl?: string;
       comment: string;
       date: string;
+      /** Art des Kommentars – steuert Icon/Farbe */
+      commentKind?: 'created' | 'deleted' | 'generic';
     }
   | {
       id: string | number;
@@ -94,10 +98,13 @@ function colorFromName(name: string): string {
 }
 
 // sprechende Zusammenfassung für "change"
-function getChangeSummary(item: Extract<FeedItem, { type: 'change' }>): string {
+function getChangeSummary(
+  item: Extract<FeedItem, { type: 'change' }>,
+): React.ReactNode {
   const { changes } = item;
   if (!changes.length) return 'hat Änderungen vorgenommen';
 
+  // Sonderfall: nur Tags
   if (changes.length === 1 && changes[0].field === 'tags') {
     const c = changes[0];
     const beforeList = (c.from ?? '')
@@ -120,15 +127,15 @@ function getChangeSummary(item: Extract<FeedItem, { type: 'change' }>): string {
     );
 
     const parts: string[] = [];
-    if (added.length) {
-      parts.push(`hinzugefügt: ${added.join(', ')}`);
-    }
-    if (removed.length) {
-      parts.push(`entfernt: ${removed.join(', ')}`);
-    }
+    if (added.length) parts.push(`hinzugefügt: ${added.join(', ')}`);
+    if (removed.length) parts.push(`entfernt: ${removed.join(', ')}`);
 
     if (parts.length > 0) {
-      return `hat Tags ${parts.join(' · ')}`;
+      return (
+        <>
+          hat Tags <em>{parts.join(' · ')}</em>
+        </>
+      );
     }
     return 'hat Tags angepasst';
   }
@@ -136,7 +143,11 @@ function getChangeSummary(item: Extract<FeedItem, { type: 'change' }>): string {
   if (changes.length === 1) {
     const c = changes[0];
     const label = c.label ?? c.field;
-    return `hat ${label} geändert`;
+    return (
+      <>
+        hat <em>{label}</em> geändert
+      </>
+    );
   }
 
   const labels = changes.map((c) => c.label ?? c.field);
@@ -144,11 +155,34 @@ function getChangeSummary(item: Extract<FeedItem, { type: 'change' }>): string {
   const maxShow = 3;
 
   if (uniqueLabels.length <= maxShow) {
-    return `hat ${uniqueLabels.join(', ')} geändert`;
+    return (
+      <>
+        hat{' '}
+        {uniqueLabels.map((label, index) => (
+          <React.Fragment key={label}>
+            <em>{label}</em>
+            {index < uniqueLabels.length - 1 ? ', ' : ' '}
+          </React.Fragment>
+        ))}
+        geändert
+      </>
+    );
   }
 
-  const first = uniqueLabels.slice(0, maxShow).join(', ');
-  return `hat ${first} und weitere geändert`;
+  const first = uniqueLabels.slice(0, maxShow);
+
+  return (
+    <>
+      hat{' '}
+      {first.map((label, index) => (
+        <React.Fragment key={label}>
+          <em>{label}</em>
+          {index < first.length - 1 ? ', ' : ' '}
+        </React.Fragment>
+      ))}
+      und weitere geändert
+    </>
+  );
 }
 
 /* ───────── Component ───────── */
@@ -168,142 +202,151 @@ export default function Feed({ items, className }: FeedProps) {
   }
 
   return (
-    <div className={clsx('h-full overflow-y-auto pr-2', className)}>
-      <ul role="list" className="pb-4">
-        {items.map((item, idx) => {
-          // Icon + Hintergrund ähnlich wie im Beispiel
-          let Icon: React.ComponentType<React.SVGProps<SVGSVGElement>> =
-            ChatBubbleLeftEllipsisIcon;
-          let iconBg = 'bg-gray-400 dark:bg-gray-600';
+    <ul
+      role="list"
+      className={clsx('pb-4', className)}
+    >
+      {items.map((item, idx) => {
+        // Icon + Hintergrund
+        let Icon: React.ComponentType<React.SVGProps<SVGSVGElement>> =
+          PencilIcon;
+        let iconBg = 'bg-gray-400 dark:bg-gray-600';
 
-          if (item.type === 'tags') {
-            Icon = TagIcon;
-            iconBg = 'bg-amber-500';
-          } else if (item.type === 'change') {
-            const isTagsOnly =
-              item.changes.length === 1 && item.changes[0].field === 'tags';
-            Icon = isTagsOnly ? TagIcon : ChatBubbleLeftEllipsisIcon;
-            iconBg = isTagsOnly ? 'bg-amber-500' : 'bg-emerald-500';
-          } else if (item.type === 'comment') {
+        if (item.type === 'tags') {
+          Icon = TagIcon;
+          iconBg = 'bg-amber-500';
+        } else if (item.type === 'change') {
+          const isTagsOnly =
+            item.changes.length === 1 && item.changes[0].field === 'tags';
+          Icon = isTagsOnly ? TagIcon : PencilIcon;
+          iconBg = isTagsOnly ? 'bg-amber-500' : 'bg-cyan-500';
+        } else if (item.type === 'comment') {
+          if (item.commentKind === 'created') {
+            Icon = PlusIcon;
+            iconBg = 'bg-emerald-500';
+          } else if (item.commentKind === 'deleted') {
+            Icon = TrashIcon;
+            iconBg = 'bg-rose-500';
+          } else {
             iconBg = colorFromName(item.person.name);
-          } else if (item.type === 'assignment') {
-            iconBg = 'bg-indigo-500';
           }
+        } else if (item.type === 'assignment') {
+          iconBg = 'bg-indigo-500';
+        }
 
-          // Textinhalt ähnlich wie "content + target"
-          let content: React.ReactNode = null;
-
-          if (item.type === 'comment') {
-            content = (
+        // Textinhalt (content) – dein bisheriger Code unverändert:
+        let content: React.ReactNode = null;
+        if (item.type === 'comment') {
+          content = (
+            <p className="text-xs text-gray-500 dark:text-gray-400">
+              <span className="font-medium text-gray-900 dark:text-white">
+                {item.person.name}
+              </span>{' '}
+              <span className="text-gray-300 dark:text-gray-200">
+                {item.comment}
+              </span>
+            </p>
+          );
+        } else if (item.type === 'assignment') {
+          content = (
+            <p className="text-xs text-gray-500 dark:text-gray-400">
+              <span className="font-medium text-gray-900 dark:text-white">
+                {item.person.name}
+              </span>{' '}
+              hat{' '}
+              <span className="font-medium text-gray-900 dark:text-white">
+                {item.assigned.name}
+              </span>{' '}
+              zugewiesen.
+            </p>
+          );
+        } else if (item.type === 'tags') {
+          content = (
+            <p className="text-xs text-gray-500 dark:text-gray-400">
+              <span className="font-medium text-gray-900 dark:text-white">
+                {item.person.name}
+              </span>{' '}
+              hat Tags hinzugefügt:{' '}
+              <span className="font-medium text-gray-900 dark:text-gray-100">
+                {item.tags.map((t) => t.name).join(', ')}
+              </span>
+            </p>
+          );
+        } else if (item.type === 'change') {
+          const summary = getChangeSummary(item);
+          content = (
+            <div className="space-y-1">
               <p className="text-xs text-gray-500 dark:text-gray-400">
                 <span className="font-medium text-gray-900 dark:text-white">
                   {item.person.name}
                 </span>{' '}
-                hat kommentiert:{' '}
-                <span className="text-gray-300 dark:text-gray-200">
-                  {item.comment}
-                </span>
+                {summary}
               </p>
-            );
-          } else if (item.type === 'assignment') {
-            content = (
-              <p className="text-xs text-gray-500 dark:text-gray-400">
-                <span className="font-medium text-gray-900 dark:text-white">
-                  {item.person.name}
-                </span>{' '}
-                hat{' '}
-                <span className="font-medium text-gray-900 dark:text-white">
-                  {item.assigned.name}
-                </span>{' '}
-                zugewiesen.
-              </p>
-            );
-          } else if (item.type === 'tags') {
-            content = (
-              <p className="text-xs text-gray-500 dark:text-gray-400">
-                <span className="font-medium text-gray-900 dark:text-white">
-                  {item.person.name}
-                </span>{' '}
-                hat Tags hinzugefügt:{' '}
-                <span className="font-medium text-gray-900 dark:text-gray-100">
-                  {item.tags.map((t) => t.name).join(', ')}
-                </span>
-              </p>
-            );
-          } else if (item.type === 'change') {
-            const summary = getChangeSummary(item);
-            content = (
-              <div className="space-y-1">
-                <p className="text-xs text-gray-500 dark:text-gray-400">
-                  <span className="font-medium text-gray-900 dark:text-white">
-                    {item.person.name}
-                  </span>{' '}
-                  {summary}
-                </p>
-                {item.changes.length > 0 && (
-                  <p className="text-[11px] text-gray-400 dark:text-gray-500">
-                    {item.changes.slice(0, 2).map((c, i) => (
-                      <span
-                        key={`${c.field}-${i}`}
-                        className="flex flex-wrap items-baseline gap-x-1"
-                      >
-                        <span className="line-through text-red-500/80 dark:text-red-400/90">
-                          {c.from ?? '—'}
-                        </span>
-                        <span className="text-gray-400">→</span>
-                        <span className="font-medium text-emerald-600 dark:text-emerald-400">
-                          {c.to ?? '—'}
-                        </span>
-                        {i < Math.min(2, item.changes.length) - 1 && (
-                          <span className="mx-1 text-gray-500 dark:text-gray-600">·</span>
-                        )}
-                      </span>
-                    ))}
-                    {item.changes.length > 2 && (
-                      <span className="ml-1 text-gray-500 dark:text-gray-600">· …</span>
-                    )}
-                  </p>
-                )}
-              </div>
-            );
-          }
-
-          return (
-            <li key={item.id}>
-              <div className="relative pb-6">
-                {idx !== items.length - 1 ? (
-                  <span
-                    aria-hidden="true"
-                    className="absolute top-4 left-4 -ml-px h-full w-0.5 bg-gray-200 dark:bg-white/10"
-                  />
-                ) : null}
-
-                <div className="relative flex space-x-3">
-                  {/* Icon-Kreis wie im Beispiel */}
-                  <div>
+              {item.changes.length > 0 && (
+                <p className="text-[11px] text-gray-400 dark:text-gray-500">
+                  {item.changes.slice(0, 2).map((c, i) => (
                     <span
-                      className={classNames(
-                        iconBg,
-                        'flex size-8 items-center justify-center rounded-full',
-                      )}
+                      key={`${c.field}-${i}`}
+                      className="flex flex-wrap items-baseline gap-x-1"
                     >
-                      <Icon aria-hidden="true" className="size-4 text-white" />
+                      <span className="line-through text-red-500/80 dark:text-red-400/90">
+                        {c.from ?? '—'}
+                      </span>
+                      <span className="text-gray-400">→</span>
+                      <span className="font-medium text-emerald-600 dark:text-emerald-400">
+                        {c.to ?? '—'}
+                      </span>
+                      {i < Math.min(2, item.changes.length) - 1 && (
+                        <span className="mx-1 text-gray-500 dark:text-gray-600">
+                          ·
+                        </span>
+                      )}
                     </span>
-                  </div>
+                  ))}
+                  {item.changes.length > 2 && (
+                    <span className="ml-1 text-gray-500 dark:text-gray-600">
+                      · …
+                    </span>
+                  )}
+                </p>
+              )}
+            </div>
+          );
+        }
 
-                  {/* Text + Datum rechts */}
-                  <div className="flex min-w-0 flex-1 justify-between space-x-4 pt-1.5">
-                    <div>{content}</div>
-                    <div className="whitespace-nowrap text-right text-[11px] text-gray-500 dark:text-gray-400">
-                      {item.date}
-                    </div>
+        return (
+          <li key={item.id}>
+            <div className="relative pb-6">
+              {idx !== items.length - 1 ? (
+                <span
+                  aria-hidden="true"
+                  className="absolute top-4 left-4 -ml-px h-full w-0.5 bg-gray-200 dark:bg-white/10"
+                />
+              ) : null}
+
+              <div className="relative flex space-x-3">
+                <div>
+                  <span
+                    className={classNames(
+                      iconBg,
+                      'flex size-8 items-center justify-center rounded-full',
+                    )}
+                  >
+                    <Icon aria-hidden="true" className="size-4 text-white" />
+                  </span>
+                </div>
+
+                <div className="flex min-w-0 flex-1 justify-between space-x-4 pt-1.5">
+                  <div>{content}</div>
+                  <div className="whitespace-nowrap text-right text-[11px] text-gray-500 dark:text-gray-400">
+                    {item.date}
                   </div>
                 </div>
               </div>
-            </li>
-          );
-        })}
-      </ul>
-    </div>
+            </div>
+          </li>
+        );
+      })}
+    </ul>
   );
-}
+}
\ No newline at end of file
diff --git a/components/ui/Modal.tsx b/components/ui/Modal.tsx
index b599201..53f1ae4 100644
--- a/components/ui/Modal.tsx
+++ b/components/ui/Modal.tsx
@@ -10,6 +10,7 @@ import {
 } from '@headlessui/react';
 import { XMarkIcon } from '@heroicons/react/24/outline';
 import clsx from 'clsx';
+import Button from './Button';
 
 export type ModalTone = 'default' | 'success' | 'danger' | 'warning' | 'info';
 export type ModalVariant = 'centered' | 'alert';
@@ -52,15 +53,19 @@ export interface ModalProps {
 
   /**
    * Wenn gesetzt, wird dieser Footer anstelle der auto-generierten Buttons gerendert.
-   * Damit kannst du komplett eigene Layouts bauen.
    */
   footer?: React.ReactNode;
 
   /**
    * Optionaler Inhalt für eine rechte Sidebar (z.B. Geräthistorie).
-   * Auf kleinen Screens unten angehängt, ab sm rechts als Spalte.
    */
   sidebar?: React.ReactNode;
+
+  /**
+   * Zusätzlicher Inhalt direkt UNTER dem Titel im Header (z.B. Tabs).
+   * Liegt außerhalb des scrollbaren Body-Bereichs.
+   */
+  headerExtras?: React.ReactNode;
 }
 
 /* ───────── Layout-Helfer ───────── */
@@ -94,27 +99,8 @@ const toneStyles: Record<
 const sizeClasses: Record<ModalSize, string> = {
   sm: 'sm:max-w-sm',
   md: 'sm:max-w-lg',
-  lg: 'sm:max-w-3xl', // ein bisschen breiter für Sidebar
-  xl: 'sm:max-w-5xl', // ein bisschen breiter für Sidebar
-};
-
-const baseButtonClasses =
-  'inline-flex w-full justify-center rounded-md px-3 py-2 text-sm font-semibold shadow-xs ' +
-  'focus-visible:outline-2 focus-visible:outline-offset-2 ';
-
-const buttonVariantClasses: Record<
-  NonNullable<ModalAction['variant']>,
-  string
-> = {
-  primary:
-    'bg-indigo-600 text-white hover:bg-indigo-500 focus-visible:outline-indigo-600 ' +
-    'dark:bg-indigo-500 dark:hover:bg-indigo-400 dark:focus-visible:outline-indigo-500 dark:shadow-none',
-  secondary:
-    'bg-white text-gray-900 inset-ring-1 inset-ring-gray-300 hover:bg-gray-50 ' +
-    'dark:bg-white/10 dark:text-white dark:shadow-none dark:inset-ring-white/5 dark:hover:bg-white/20',
-  danger:
-    'bg-red-600 text-white hover:bg-red-500 focus-visible:outline-red-600 ' +
-    'dark:bg-red-500 dark:hover:bg-red-400 dark:shadow-none',
+  lg: 'sm:max-w-3xl',
+  xl: 'sm:max-w-5xl',
 };
 
 function renderActionButton(
@@ -123,15 +109,29 @@ function renderActionButton(
 ): React.ReactNode {
   const variant = action.variant ?? 'primary';
 
+  let buttonVariant: 'primary' | 'secondary' | 'soft' = 'primary';
+  let tone: 'indigo' | 'gray' | 'rose' = 'indigo';
+
+  if (variant === 'secondary') {
+    buttonVariant = 'secondary';
+    tone = 'gray';
+  } else if (variant === 'danger') {
+    buttonVariant = 'primary';
+    tone = 'rose';
+  }
+
   return (
-    <button
+    <Button
       type="button"
       onClick={action.onClick}
-      data-autofocus={action.autoFocus ? true : undefined}
-      className={clsx(baseButtonClasses, buttonVariantClasses[variant], extraClasses)}
+      autoFocus={action.autoFocus}
+      variant={buttonVariant}
+      tone={tone}
+      size="lg"
+      className={clsx('w-full', extraClasses)}
     >
       {action.label}
-    </button>
+    </Button>
   );
 }
 
@@ -153,10 +153,12 @@ export function Modal({
   useGrayFooter = false,
   footer,
   sidebar,
+  headerExtras,
 }: ModalProps) {
   const toneStyle = toneStyles[tone];
   const panelSizeClasses = sizeClasses[size];
   const hasActions = !!primaryAction || !!secondaryAction;
+  const hasBothActions = !!primaryAction && !!secondaryAction;
 
   const isAlert = variant === 'alert';
   const bodyContent = children ?? description;
@@ -169,11 +171,11 @@ export function Modal({
       />
 
       <div className="fixed inset-0 z-50 w-screen overflow-y-auto">
-        <div className="flex min-h-full items-end justify-center p-4 text-center sm:items-center sm:p-0">
+        <div className="flex min-h-full items-start justify-center p-4 text-center sm:p-8">
           <DialogPanel
             transition
             className={clsx(
-              'relative flex max-h-[90vh] w-full flex-col transform overflow-hidden rounded-lg bg-white text-left shadow-xl transition-all ' +
+              'relative flex w-full max-h-[calc(100vh-8rem)] lg:max-h-[800px] flex-col transform overflow-hidden rounded-lg bg-white text-left shadow-xl transition-all ' +
                 'data-closed:translate-y-4 data-closed:opacity-0 data-enter:duration-300 data-enter:ease-out ' +
                 'data-leave:duration-200 data-leave:ease-in sm:my-8 data-closed:sm:translate-y-0 data-closed:sm:scale-95 ' +
                 'dark:bg-gray-800 dark:outline dark:-outline-offset-1 dark:outline-white/10',
@@ -194,9 +196,9 @@ export function Modal({
               </div>
             )}
 
-            {/* Header + Body + Sidebar */}
-            <div className="flex-1 overflow-hidden bg-white px-4 pt-5 pb-4 sm:p-6 sm:pb-4 dark:bg-gray-800">
-              {/* Header (Icon + Titel + optionale Beschreibung) */}
+            {/* HEADER + MAIN (Body+Sidebar) */}
+            <div className="flex-1 flex flex-col min-h-0 bg-white px-4 pt-5 pb-4 sm:p-6 sm:pb-4 dark:bg-gray-800 overflow-hidden">
+              {/* Header */}
               <div
                 className={clsx(
                   'flex',
@@ -245,28 +247,33 @@ export function Modal({
                     </DialogTitle>
                   )}
 
-                  {/* Beschreibung nur anzeigen, wenn keine eigenen Children übergeben wurden */}
                   {!children && description && (
                     <p className="mt-2 text-sm text-gray-500 dark:text-gray-400">
                       {description}
                     </p>
                   )}
+
+                  {headerExtras && (
+                    <div className="mt-4 w-full">{headerExtras}</div>
+                  )}
                 </div>
               </div>
 
-              {/* Body + Sidebar */ }
+              {/* MAIN: Body + Sidebar – nimmt den Rest der Höhe ein */}
               {(bodyContent || sidebar) && (
                 <div
                   className={clsx(
-                    'mt-6',
-                    // vorher: sidebar && 'sm:mt-8 sm:flex sm:items-start sm:gap-6',
-                    sidebar && 'sm:mt-8 sm:flex sm:items-stretch sm:gap-6',
+                    'mt-6 flex flex-col min-h-0',
+                    sidebar
+                      ? 'sm:mt-8 sm:flex-row sm:items-stretch sm:gap-6'
+                      : 'overflow-y-auto' // nur ohne Sidebar soll der Body global scrollen
                   )}
                 >
+                  {/* Linker Inhalt (Details / Formulare) */}
                   {bodyContent && (
                     <div
                       className={clsx(
-                        'flex-1 text-left',
+                        'flex-1 min-h-0 overflow-y-auto text-left',
                         !sidebar && 'mx-auto max-w-2xl',
                       )}
                     >
@@ -274,8 +281,9 @@ export function Modal({
                     </div>
                   )}
 
+                  {/* Rechte Sidebar (QR + Verlauf) */}
                   {sidebar && (
-                    <aside className="border-t border-gray-200 text-left text-sm sm:flex sm:h-full sm:w-80 sm:shrink-0 sm:border-l sm:border-t-0 sm:pl-4 dark:border-white/10" >
+                    <aside className="sm:min-h-0 sm:overflow-hidden">
                       {sidebar}
                     </aside>
                   )}
@@ -292,32 +300,25 @@ export function Modal({
                   useGrayFooter
                     ? 'bg-gray-50 px-4 py-3 sm:px-6 dark:bg-gray-700/25'
                     : 'px-4 py-3 sm:px-6',
-                  isAlert
-                    ? 'sm:flex sm:flex-row-reverse sm:gap-3'
-                    : secondaryAction
-                      ? 'sm:mt-2 sm:grid sm:grid-flow-row-dense sm:grid-cols-2 sm:gap-3'
-                      : 'sm:mt-2',
                 )}
               >
-                {primaryAction &&
-                  renderActionButton(
-                    primaryAction,
-                    isAlert
-                      ? 'sm:w-auto'
-                      : secondaryAction
-                        ? 'sm:col-start-2'
-                        : '',
-                  )}
-
-                {secondaryAction &&
-                  renderActionButton(
-                    { ...secondaryAction, variant: secondaryAction.variant ?? 'secondary' },
-                    clsx(
-                      'mt-3 sm:mt-0',
-                      isAlert && 'sm:w-auto sm:mr-3',
-                      !useGrayFooter && 'bg-white',
-                    ),
+                <div
+                  className={clsx(
+                    'flex flex-col gap-3',
+                    hasBothActions && 'sm:flex-row-reverse',
                   )}
+                >
+                  {primaryAction &&
+                    renderActionButton(
+                      primaryAction,
+                      hasBothActions ? 'flex-1' : undefined,
+                    )}
+                  {secondaryAction &&
+                    renderActionButton(
+                      { ...secondaryAction, variant: secondaryAction.variant ?? 'secondary' },
+                      hasBothActions ? 'flex-1' : undefined,
+                    )}
+                </div>
               </div>
             ) : null}
           </DialogPanel>
@@ -328,3 +329,4 @@ export function Modal({
 }
 
 export default Modal;
+
diff --git a/components/ui/Table.tsx b/components/ui/Table.tsx
index 0e47520..1dc57dd 100644
--- a/components/ui/Table.tsx
+++ b/components/ui/Table.tsx
@@ -81,11 +81,21 @@ export default function Table<T>(props: TableProps<T>) {
       if (va == null) return sort.direction === 'asc' ? -1 : 1;
       if (vb == null) return sort.direction === 'asc' ? 1 : -1;
 
-      // Numbers
+      // Reine Numbers
       if (typeof va === 'number' && typeof vb === 'number') {
         return sort.direction === 'asc' ? va - vb : vb - va;
       }
 
+      // Numerische Strings wie "1", "123", "42"
+      if (typeof va === 'string' && typeof vb === 'string') {
+        const na = Number(va);
+        const nb = Number(vb);
+
+        if (!Number.isNaN(na) && !Number.isNaN(nb)) {
+          return sort.direction === 'asc' ? na - nb : nb - na;
+        }
+      }
+
       // Date / ISO-String
       const sa = va instanceof Date ? va.getTime() : String(va);
       const sb = vb instanceof Date ? vb.getTime() : String(vb);
@@ -197,7 +207,7 @@ export default function Table<T>(props: TableProps<T>) {
                     key={String(col.key)}
                     scope="col"
                     className={classNames(
-                      'py-3.5 px-4 text-left text-sm font-semibold text-gray-900 dark:text-white',
+                      'py-3.5 px-2 text-left text-sm font-semibold text-gray-900 dark:text-white',
                       col.headerClassName,
                       isHideable
                         ? 'hidden lg:table-cell'
@@ -238,7 +248,7 @@ export default function Table<T>(props: TableProps<T>) {
               {renderActions && (
                 <th
                   scope="col"
-                  className="py-3.5 px-4 text-sm font-semibold text-gray-900 dark:text-white"
+                  className="py-3.5 px-2 text-sm font-semibold text-gray-900 dark:text-white"
                 >
                   {actionsHeader}
                 </th>
@@ -256,7 +266,7 @@ export default function Table<T>(props: TableProps<T>) {
                 className={classNames(isSelected && 'bg-gray-50 dark:bg-gray-800/60')}
               >
                 {selectable && (
-                  <td className="px-4">
+                  <td className="px-2">
                       <div className="group grid size-4 grid-cols-1">
                         <input
                           type="checkbox"
@@ -292,7 +302,7 @@ export default function Table<T>(props: TableProps<T>) {
                     <td
                       key={String(col.key)}
                       className={classNames(
-                        'px-4 py-3 text-sm whitespace-nowrap text-gray-700 dark:text-gray-300',
+                        'px-2 py-3 text-sm whitespace-nowrap text-gray-700 dark:text-gray-300',
                         col.cellClassName,
                         col.canHide && 'hidden lg:table-cell', // <-- HIER
                       )}
@@ -302,7 +312,7 @@ export default function Table<T>(props: TableProps<T>) {
                   ))}
 
                   {renderActions && (
-                    <td className="px-4 py-3 text-sm whitespace-nowrap text-right">
+                    <td className="px-2 py-3 text-sm whitespace-nowrap text-right">
                       {renderActions(row)}
                     </td>
                   )}
@@ -314,7 +324,7 @@ export default function Table<T>(props: TableProps<T>) {
               <tr>
                 <td
                   colSpan={columns.length + (selectable ? 1 : 0) + (renderActions ? 1 : 0)}
-                  className="px-4 py-6 text-center text-sm text-gray-500 dark:text-gray-400"
+                  className="px-2 py-6 text-center text-sm text-gray-500 dark:text-gray-400"
                 >
                   Keine Daten vorhanden.
                 </td>
diff --git a/components/ui/Tabs.tsx b/components/ui/Tabs.tsx
index 8c3cb85..caafbc8 100644
--- a/components/ui/Tabs.tsx
+++ b/components/ui/Tabs.tsx
@@ -1,62 +1,83 @@
-// /components/ui/Tabs.tsx
+// components/ui/Tabs.tsx
 
-'use client'
+'use client';
 
-import * as React from 'react'
+import { ChevronDownIcon } from '@heroicons/react/16/solid';
+import clsx from 'clsx';
+import * as React from 'react';
 
 export type TabItem = {
-  id: string
-  label: string
-}
+  id: string;
+  label: string;
+};
 
-export type TabsProps = {
-  tabs: TabItem[]
-  defaultTabId?: string
-  onChange?(id: string): void
-  className?: string
-}
+type TabsProps = {
+  tabs: TabItem[];
+  /** aktuell ausgewählter Tab (id) */
+  value: string;
+  /** Callback bei Wechsel */
+  onChange: (id: string) => void;
+  className?: string;
+  /** Optional eigenes aria-label */
+  ariaLabel?: string;
+};
 
-export function Tabs({ tabs, defaultTabId, onChange, className }: TabsProps) {
-  const [activeId, setActiveId] = React.useState(
-    defaultTabId ?? (tabs[0]?.id ?? ''),
-  )
-
-  const handleClick = (id: string) => {
-    setActiveId(id)
-    onChange?.(id)
-  }
+export default function Tabs({
+  tabs,
+  value,
+  onChange,
+  className,
+  ariaLabel = 'Ansicht auswählen',
+}: TabsProps) {
+  const current = tabs.find((t) => t.id === value) ?? tabs[0];
 
   return (
-    <div
-      className={[
-        'border-b border-gray-200 dark:border-white/10',
-        className,
-      ]
-        .filter(Boolean)
-        .join(' ')}
-    >
-      <nav className="-mb-px flex space-x-8" aria-label="Tabs">
-        {tabs.map((tab) => {
-          const isActive = tab.id === activeId
-          return (
-            <button
-              key={tab.id}
-              type="button"
-              onClick={() => handleClick(tab.id)}
-              className={[
-                'whitespace-nowrap border-b-2 px-1 pb-3 pt-2 text-sm/6 font-semibold transition-colors',
-                isActive
-                  ? 'border-indigo-500 text-indigo-600 dark:border-indigo-400 dark:text-indigo-300'
-                  : 'border-transparent text-gray-500 hover:border-gray-300 hover:text-gray-700 dark:text-gray-400 dark:hover:text-gray-200',
-              ]
-                .filter(Boolean)
-                .join(' ')}
-            >
+    <div className={className}>
+      {/* Mobile: Select + Chevron */}
+      <div className="grid grid-cols-1 sm:hidden">
+        <select
+          value={current.id}
+          onChange={(e) => onChange(e.target.value)}
+          aria-label={ariaLabel}
+          className="col-start-1 row-start-1 w-full appearance-none rounded-md bg-white py-2 pr-8 pl-3 text-base text-gray-900 outline-1 -outline-offset-1 outline-gray-300 focus:outline-2 focus:-outline-offset-2 focus:outline-indigo-600 dark:bg-white/5 dark:text-gray-100 dark:outline-white/10 dark:*:bg-gray-800 dark:focus:outline-indigo-500"
+        >
+          {tabs.map((tab) => (
+            <option key={tab.id} value={tab.id}>
               {tab.label}
-            </button>
-          )
-        })}
-      </nav>
+            </option>
+          ))}
+        </select>
+        <ChevronDownIcon
+          aria-hidden="true"
+          className="pointer-events-none col-start-1 row-start-1 mr-2 size-5 self-center justify-self-end fill-gray-500 dark:fill-gray-400"
+        />
+      </div>
+
+      {/* Desktop: Underline-Tabs */}
+      <div className="hidden sm:block">
+        <div className="border-b border-gray-200 dark:border-white/10">
+          <nav aria-label={ariaLabel} className="-mb-px flex space-x-8">
+            {tabs.map((tab) => {
+              const isCurrent = tab.id === current.id;
+              return (
+                <button
+                  key={tab.id}
+                  type="button"
+                  onClick={() => onChange(tab.id)}
+                  className={clsx(
+                    isCurrent
+                      ? 'border-indigo-500 text-indigo-600 dark:border-indigo-400 dark:text-indigo-400'
+                      : 'border-transparent text-gray-500 hover:border-gray-300 hover:text-gray-700 dark:text-gray-400 dark:hover:border-white/20 dark:hover:text-gray-200',
+                    'border-b-2 px-1 py-3 text-sm font-medium whitespace-nowrap',
+                  )}
+                >
+                  {tab.label}
+                </button>
+              );
+            })}
+          </nav>
+        </div>
+      </div>
     </div>
-  )
+  );
 }
diff --git a/package-lock.json b/package-lock.json
index 989e331..ced7d9c 100644
--- a/package-lock.json
+++ b/package-lock.json
@@ -11,10 +11,13 @@
         "@headlessui/react": "^2.2.9",
         "@heroicons/react": "^2.2.0",
         "@prisma/client": "^6.19.0",
+        "@zxing/browser": "^0.1.5",
+        "@zxing/library": "^0.21.3",
         "bcryptjs": "^3.0.3",
         "next": "16.0.3",
         "next-auth": "^4.24.13",
         "postcss": "^8.5.6",
+        "qrcode.react": "^4.2.0",
         "react": "19.2.0",
         "react-dom": "19.2.0",
         "socket.io": "^4.8.1",
@@ -2533,6 +2536,41 @@
         "win32"
       ]
     },
+    "node_modules/@zxing/browser": {
+      "version": "0.1.5",
+      "resolved": "https://registry.npmjs.org/@zxing/browser/-/browser-0.1.5.tgz",
+      "integrity": "sha512-4Lmrn/il4+UNb87Gk8h1iWnhj39TASEHpd91CwwSJtY5u+wa0iH9qS0wNLAWbNVYXR66WmT5uiMhZ7oVTrKfxw==",
+      "license": "MIT",
+      "optionalDependencies": {
+        "@zxing/text-encoding": "^0.9.0"
+      },
+      "peerDependencies": {
+        "@zxing/library": "^0.21.0"
+      }
+    },
+    "node_modules/@zxing/library": {
+      "version": "0.21.3",
+      "resolved": "https://registry.npmjs.org/@zxing/library/-/library-0.21.3.tgz",
+      "integrity": "sha512-hZHqFe2JyH/ZxviJZosZjV+2s6EDSY0O24R+FQmlWZBZXP9IqMo7S3nb3+2LBWxodJQkSurdQGnqE7KXqrYgow==",
+      "license": "MIT",
+      "peer": true,
+      "dependencies": {
+        "ts-custom-error": "^3.2.1"
+      },
+      "engines": {
+        "node": ">= 10.4.0"
+      },
+      "optionalDependencies": {
+        "@zxing/text-encoding": "~0.9.0"
+      }
+    },
+    "node_modules/@zxing/text-encoding": {
+      "version": "0.9.0",
+      "resolved": "https://registry.npmjs.org/@zxing/text-encoding/-/text-encoding-0.9.0.tgz",
+      "integrity": "sha512-U/4aVJ2mxI0aDNI8Uq0wEhMgY+u4CNtEb0om3+y3+niDAsoTCOB33UF0sxpzqzdqXLqmvc+vZyAt4O8pPdfkwA==",
+      "license": "(Unlicense OR Apache-2.0)",
+      "optional": true
+    },
     "node_modules/accepts": {
       "version": "1.3.8",
       "resolved": "https://registry.npmjs.org/accepts/-/accepts-1.3.8.tgz",
@@ -6400,6 +6438,15 @@
       ],
       "license": "MIT"
     },
+    "node_modules/qrcode.react": {
+      "version": "4.2.0",
+      "resolved": "https://registry.npmjs.org/qrcode.react/-/qrcode.react-4.2.0.tgz",
+      "integrity": "sha512-QpgqWi8rD9DsS9EP3z7BT+5lY5SFhsqGjpgW5DY/i3mK4M9DTBNz3ErMi8BWYEfI3L0d8GIbGmcdFAS1uIRGjA==",
+      "license": "ISC",
+      "peerDependencies": {
+        "react": "^16.8.0 || ^17.0.0 || ^18.0.0 || ^19.0.0"
+      }
+    },
     "node_modules/queue-microtask": {
       "version": "1.2.3",
       "resolved": "https://registry.npmjs.org/queue-microtask/-/queue-microtask-1.2.3.tgz",
@@ -7324,6 +7371,15 @@
         "typescript": ">=4.8.4"
       }
     },
+    "node_modules/ts-custom-error": {
+      "version": "3.3.1",
+      "resolved": "https://registry.npmjs.org/ts-custom-error/-/ts-custom-error-3.3.1.tgz",
+      "integrity": "sha512-5OX1tzOjxWEgsr/YEUWSuPrQ00deKLh6D7OTWcvNHm12/7QPyRh8SYpyWvA4IZv8H/+GQWQEh/kwo95Q9OVW1A==",
+      "license": "MIT",
+      "engines": {
+        "node": ">=14.0.0"
+      }
+    },
     "node_modules/ts-node": {
       "version": "10.9.2",
       "resolved": "https://registry.npmjs.org/ts-node/-/ts-node-10.9.2.tgz",
diff --git a/package.json b/package.json
index 9b3fca8..0ca5c4f 100644
--- a/package.json
+++ b/package.json
@@ -13,10 +13,13 @@
     "@headlessui/react": "^2.2.9",
     "@heroicons/react": "^2.2.0",
     "@prisma/client": "^6.19.0",
+    "@zxing/browser": "^0.1.5",
+    "@zxing/library": "^0.21.3",
     "bcryptjs": "^3.0.3",
     "next": "16.0.3",
     "next-auth": "^4.24.13",
     "postcss": "^8.5.6",
+    "qrcode.react": "^4.2.0",
     "react": "19.2.0",
     "react-dom": "19.2.0",
     "socket.io": "^4.8.1",
diff --git a/prisma/dev.db b/prisma/dev.db
index 7f2338c..2e5fc07 100644
Binary files a/prisma/dev.db and b/prisma/dev.db differ
diff --git a/prisma/migrations/20251118082710_add_device_history_changed_by/migration.sql b/prisma/migrations/20251118082710_add_device_history_changed_by/migration.sql
new file mode 100644
index 0000000..29cd6d5
--- /dev/null
+++ b/prisma/migrations/20251118082710_add_device_history_changed_by/migration.sql
@@ -0,0 +1,5 @@
+-- DropIndex
+DROP INDEX "DeviceHistory_changedById_idx";
+
+-- DropIndex
+DROP INDEX "DeviceHistory_deviceId_changedAt_idx";
diff --git a/prisma/schema.prisma b/prisma/schema.prisma
index c0ad748..20fd3ea 100644
--- a/prisma/schema.prisma
+++ b/prisma/schema.prisma
@@ -136,23 +136,14 @@ enum DeviceChangeType {
 
 model DeviceHistory {
   id         String           @id @default(cuid())
-
   deviceId   String
   device     Device           @relation(fields: [deviceId], references: [inventoryNumber])
-
   changeType DeviceChangeType
-
   snapshot   Json
   changedAt  DateTime         @default(now())
-
-  // 🔹 FK-Spalte
   changedById String?
-
-  // 🔹 Relation zu User
   changedBy   User? @relation("DeviceHistoryChangedBy", fields: [changedById], references: [id])
-
-  @@index([deviceId, changedAt])
-  @@index([changedById])
 }
 
 
+