diff --git a/AGENTS.md b/AGENTS.md
index 0f178a0..09eacf1 100644
--- a/AGENTS.md
+++ b/AGENTS.md
@@ -84,7 +84,7 @@ flow:
 | **Build & Dev** | Vite 8 (`type: module`) | Dev server on `4209`, HTTPS on `4308`, proxies `/api` → `http://localhost:4208` |
 | **Framework** | React 19 (`react`, `react-dom`) | Uses `PureComponent` (with Automats & dashgui) and modern function components |
 | **Routing** | `react-router-dom` v7 | Configured in [src/appRouter.jsx](file:///home/seb/src/dashfront/src/appRouter.jsx) with HMR router preservation |
-| **UI & Theming** | MUI 9 (`@mui/material`, Emotion) | Custom theme in `src/theme/`, base background `#c5ddd8` in `src/colors.js` |
+| **UI & Theming** | MUI 9 (`@mui/material`, Emotion) | Custom theme in `src/theme/`, base background `#85b7ad` in `src/colors.js` |
 | **Shared GUI** | `dashgui` (`file:../dashgui`) | `PanelTile`, `RecordList`, `Tile`, `SingleLineTextEdit`, `ElevatedPill` |
 | **State Management** | `react-automat` | Single state layer for all domain & configuration data (articles, categories, company, brands, units, POS terminals, session) |
 | **Notifications** | `notistack` | `useSnackbar()` / `<SnackbarProvider>` in [src/main.jsx](file:///home/seb/src/dashfront/src/main.jsx) |
diff --git a/index.html b/index.html
index da05854..1eaa375 100644
--- a/index.html
+++ b/index.html
@@ -1,56 +1,59 @@
 <!doctype html>
 <html lang="en">
-  <head>
-    <meta charset="UTF-8" />
-    <link rel="icon" type="image/svg+xml" href="/favicon.svg" />
-    <link rel="apple-touch-icon" href="/icons/icon-192.png" />
-    <meta name="theme-color" content="#3b5bdb" />
-    <meta name="viewport" content="width=device-width, initial-scale=1.0, maximum-scale=1.0, user-scalable=no" />
-    <title>Dashfront</title>
-    <style>
-      html,
-      body,
-      #root {
-        min-height: 100%;
-        background-color: #c5ddd8;
-      }
 
-      html,
-      body {
-        overscroll-behavior-y: none;
-        touch-action: manipulation;
-      }
+<head>
+  <meta charset="UTF-8" />
+  <link rel="icon" type="image/svg+xml" href="/favicon.svg" />
+  <link rel="apple-touch-icon" href="/icons/icon-192.png" />
+  <meta name="theme-color" content="#3b5bdb" />
+  <meta name="viewport" content="width=device-width, initial-scale=1.0, maximum-scale=1.0, user-scalable=no" />
+  <title>Dashfront</title>
+  <style>
+    html,
+    body,
+    #root {
+      min-height: 100%;
+      background-color: #85b7ad;
+    }
 
-      html {
-        scrollbar-gutter: stable;
-      }
-    </style>
-  </head>
-  <body>
-    <div id="root"></div>
-    <script>
-      (function () {
-        var host = location.hostname;
-        if (host !== 'localhost' && host !== '127.0.0.1') return;
-        if (!navigator.serviceWorker) return;
-        var hadSw = false;
-        navigator.serviceWorker.getRegistrations().then(function (regs) {
-          hadSw = regs.length > 0;
-          return Promise.all(regs.map(function (r) { return r.unregister(); }));
-        }).then(function () {
-          if (!window.caches) return hadSw;
-          return caches.keys().then(function (keys) {
-            return Promise.all(keys.map(function (k) { return caches.delete(k); }))
-              .then(function () { return hadSw; });
-          });
-        }).then(function (reload) {
-          if (reload && !sessionStorage.getItem('dashfront-sw-cleared')) {
-            sessionStorage.setItem('dashfront-sw-cleared', '1');
-            location.reload();
-          }
+    html,
+    body {
+      overscroll-behavior-y: none;
+      touch-action: manipulation;
+    }
+
+    html {
+      scrollbar-gutter: stable;
+    }
+  </style>
+</head>
+
+<body>
+  <div id="root"></div>
+  <script>
+    (function () {
+      var host = location.hostname;
+      if (host !== 'localhost' && host !== '127.0.0.1') return;
+      if (!navigator.serviceWorker) return;
+      var hadSw = false;
+      navigator.serviceWorker.getRegistrations().then(function (regs) {
+        hadSw = regs.length > 0;
+        return Promise.all(regs.map(function (r) { return r.unregister(); }));
+      }).then(function () {
+        if (!window.caches) return hadSw;
+        return caches.keys().then(function (keys) {
+          return Promise.all(keys.map(function (k) { return caches.delete(k); }))
+            .then(function () { return hadSw; });
         });
-      })();
-    </script>
-    <script type="module" src="/src/main.jsx"></script>
-  </body>
-</html>
+      }).then(function (reload) {
+        if (reload && !sessionStorage.getItem('dashfront-sw-cleared')) {
+          sessionStorage.setItem('dashfront-sw-cleared', '1');
+          location.reload();
+        }
+      });
+    })();
+  </script>
+  <script type="module" src="/src/main.jsx"></script>
+</body>
+
+</html>
\ No newline at end of file
diff --git a/src/colors.js b/src/colors.js
index c1471f4..41922b7 100644
--- a/src/colors.js
+++ b/src/colors.js
@@ -1,2 +1,2 @@
 // Mirrored in index.html and index.css for paint before JS loads.
-export const MAIN_BACKGROUND = '#c5ddd8';
+export const MAIN_BACKGROUND = '#85b7ad';
diff --git a/src/components/TextInput.jsx b/src/components/TextInput.jsx
index 3dd1152..bc6e4a4 100644
--- a/src/components/TextInput.jsx
+++ b/src/components/TextInput.jsx
@@ -112,6 +112,7 @@ export default class TextInput extends Component {
 
     const mergedSlotProps = {
       ...restSlotProps,
+      ...(resolvedInputProps ? { input: resolvedInputProps } : {}),
       inputLabel: {
         ...(label ? { shrink: true } : {}),
         ...InputLabelProps,
@@ -128,7 +129,6 @@ export default class TextInput extends Component {
         autoComplete="one-time-code"
         onFocus={this.handleFocus}
         onMouseDown={this.handleMouseDown}
-        InputProps={resolvedInputProps}
         slotProps={mergedSlotProps}
         sx={resolveSx(sx)}
         {...rest}
diff --git a/src/components/article/tabs/ArticleAttributesTab.jsx b/src/components/article/tabs/ArticleAttributesTab.jsx
index 303d81b..6d40777 100644
--- a/src/components/article/tabs/ArticleAttributesTab.jsx
+++ b/src/components/article/tabs/ArticleAttributesTab.jsx
@@ -246,20 +246,19 @@ export default class ArticleAttributesTab extends PureComponent {
       const isExclusive = Boolean(targetAttr.exclusive);
       const targetValId = Number(effectiveItemId);
       const isAlreadyAssigned = assignedAttributes.some((a) => a.attributeValueId === targetValId);
+      const isMerkmalAlreadyAssigned = assignedAttributes.some((a) => a.attributeId === targetAttr.id);
+
+      if (isExclusive && isMerkmalAlreadyAssigned) {
+        enqueueSnackbar('Eindeutiges Merkmal ist bereits zugeordnet.', { variant: 'info' });
+        return;
+      }
 
       if (isAlreadyAssigned) {
         enqueueSnackbar('Bereits zugeordnet.', { variant: 'info' });
         return;
       }
 
-      const nextValues = isExclusive
-        ? [
-            ...assignedAttributes
-              .filter((a) => a.attributeId !== targetAttr.id)
-              .map((a) => a.attributeValueId),
-            targetValId,
-          ]
-        : [...assignedAttributes.map((a) => a.attributeValueId), targetValId];
+      const nextValues = [...assignedAttributes.map((a) => a.attributeValueId), targetValId];
 
       this.setState({ saving: true });
       try {
@@ -282,6 +281,13 @@ export default class ArticleAttributesTab extends PureComponent {
       if (!targetProp || !val) return;
 
       const isExclusive = Boolean(targetProp.exclusive);
+      const isMerkmalAlreadyAssigned = assignedProperties.some((p) => p.propertyId === propId);
+
+      if (isExclusive && isMerkmalAlreadyAssigned) {
+        enqueueSnackbar('Eindeutiges Merkmal ist bereits zugeordnet.', { variant: 'info' });
+        return;
+      }
+
       if (!isExclusive) {
         const isAlreadyAssigned = assignedProperties.some(
           (p) => p.propertyId === propId && p.value.trim().toLowerCase() === val.toLowerCase()
@@ -291,11 +297,8 @@ export default class ArticleAttributesTab extends PureComponent {
           return;
         }
       }
-      const sourceProps = isExclusive
-        ? assignedProperties.filter((p) => p.propertyId !== propId)
-        : assignedProperties;
       const nextProps = [
-        ...sourceProps.map((p) => ({ propertyId: p.propertyId, value: p.value, sort: p.sort })),
+        ...assignedProperties.map((p) => ({ propertyId: p.propertyId, value: p.value, sort: p.sort })),
         { propertyId: propId, value: val },
       ];
 
@@ -470,6 +473,36 @@ export default class ArticleAttributesTab extends PureComponent {
 
     assignedGroups.sort((a, b) => a.sort - b.sort || a.name.localeCompare(b.name));
 
+    const isExclusive = Boolean(selectedOption?.exclusive);
+    const isMerkmalAlreadyAssigned = isAttr
+      ? assignedAttributes.some((a) => a.attributeId === selectedOption?.id)
+      : assignedProperties.some((p) => p.propertyId === selectedOption?.id);
+
+    const isValueAlreadyAssigned = isAttr
+      ? assignedAttributes.some((a) => a.attributeValueId === Number(currentItemId))
+      : (Boolean(customValueText.trim()) && assignedProperties.some(
+          (p) => p.propertyId === selectedOption?.id && p.value.trim().toLowerCase() === customValueText.trim().toLowerCase()
+        ));
+
+    const isUniqueAlreadyAdded = isExclusive && isMerkmalAlreadyAssigned;
+
+    const isAddDisabled =
+      saving ||
+      isVariantBlocked ||
+      !selectedMerkmalKey ||
+      (isAttr ? !currentItemId || availableItems.length === 0 : !customValueText.trim()) ||
+      isUniqueAlreadyAdded ||
+      isValueAlreadyAssigned;
+
+    let addTooltipTitle = 'Hinzufügen';
+    if (isUniqueAlreadyAdded) {
+      addTooltipTitle = 'Eindeutiges Merkmal ist bereits zugeordnet';
+    } else if (isValueAlreadyAssigned) {
+      addTooltipTitle = 'Bereits zugeordnet';
+    } else if (isVariantBlocked) {
+      addTooltipTitle = 'Varianten-Merkmal kann nicht zugeordnet werden';
+    }
+
     return (
       <Box sx={{ display: 'flex', flexDirection: 'column', gap: 2 }}>
         {/* Unified Add Bar: [Merkmal ▼] [Wert ▼ / Input] [+] */}
@@ -531,16 +564,11 @@ export default class ArticleAttributesTab extends PureComponent {
             />
           )}
 
-          <Tooltip title="Hinzufügen">
+          <Tooltip title={addTooltipTitle}>
             <span>
               <IconButton
                 color="primary"
-                disabled={
-                  saving ||
-                  isVariantBlocked ||
-                  !selectedMerkmalKey ||
-                  (isAttr ? !selectedItemId || availableItems.length === 0 : !customValueText.trim())
-                }
+                disabled={isAddDisabled}
                 onClick={() => void this.handleAddItem()}
                 sx={{
                   bgcolor: 'primary.main',
diff --git a/src/index.css b/src/index.css
index 213716a..1e77cb9 100644
--- a/src/index.css
+++ b/src/index.css
@@ -5,7 +5,7 @@ html,
 body,
 #root {
   min-height: 100%;
-  background-color: #c5ddd8;
+  background-color: #85b7ad;
 }
 
 html,
@@ -30,4 +30,4 @@ html {
   box-shadow: 0 8px 20px rgba(0, 0, 0, 0.28);
   cursor: grabbing !important;
   user-select: none !important;
-}
+}
\ No newline at end of file
diff --git a/vite.config.js b/vite.config.js
index 20cc135..ade9593 100644
--- a/vite.config.js
+++ b/vite.config.js
@@ -288,45 +288,45 @@ export default defineConfig(({ command }) => ({
     nginxHeadersPreviewPlugin(),
     ...(command === 'build'
       ? [
-          VitePWA({
-            registerType: 'autoUpdate',
-            injectRegister: 'auto',
-            manifest: {
-              id: '/',
-              name: 'Dashfront',
-              short_name: 'Dashfront',
-              start_url: '/',
-              scope: '/',
-              display: 'standalone',
-              background_color: '#c5ddd8',
-              theme_color: '#3b5bdb',
-              icons: [
-                {
-                  src: '/icons/icon-192.png',
-                  sizes: '192x192',
-                  type: 'image/png',
-                },
-                {
-                  src: '/icons/icon-512.png',
-                  sizes: '512x512',
-                  type: 'image/png',
-                },
-                {
-                  src: '/icons/icon-512.png',
-                  sizes: '512x512',
-                  type: 'image/png',
-                  purpose: 'maskable',
-                },
-              ],
-            },
-            workbox: {
-              globPatterns: ['**/*.{js,css,html,ico,png,svg,webmanifest,woff2}'],
-              globIgnores: ['**/*.wasm'],
-              navigateFallback: 'index.html',
-              navigateFallbackDenylist: [/^\/api/],
-            },
-          }),
-        ]
+        VitePWA({
+          registerType: 'autoUpdate',
+          injectRegister: 'auto',
+          manifest: {
+            id: '/',
+            name: 'Dashfront',
+            short_name: 'Dashfront',
+            start_url: '/',
+            scope: '/',
+            display: 'standalone',
+            background_color: '#85b7ad',
+            theme_color: '#3b5bdb',
+            icons: [
+              {
+                src: '/icons/icon-192.png',
+                sizes: '192x192',
+                type: 'image/png',
+              },
+              {
+                src: '/icons/icon-512.png',
+                sizes: '512x512',
+                type: 'image/png',
+              },
+              {
+                src: '/icons/icon-512.png',
+                sizes: '512x512',
+                type: 'image/png',
+                purpose: 'maskable',
+              },
+            ],
+          },
+          workbox: {
+            globPatterns: ['**/*.{js,css,html,ico,png,svg,webmanifest,woff2}'],
+            globIgnores: ['**/*.wasm'],
+            navigateFallback: 'index.html',
+            navigateFallbackDenylist: [/^\/api/],
+          },
+        }),
+      ]
       : []),
   ],
   server: sharedServer,