Implemented following stuff

- Basic Material Design
- Default Component to see anything
- theme switching between light and dark
- language change between german and english

src/app/service/language.service.ts

@@ -0,0 +1,32 @@
+import { Injectable, inject, signal } from '@angular/core';
+import { TranslateService } from '@ngx-translate/core';
+import {Constants} from '../constants/Constants';
+
+type Lang = 'de' | 'en';
+
+@Injectable({ providedIn: 'root' })
+export class LanguageService {
+  private readonly translate = inject(TranslateService);
+  readonly lang = signal<Lang>(this.getInitial());
+
+  constructor() {
+    this.translate.addLangs(['de', 'en']);
+    this.translate.setFallbackLang('en');
+    this.use(this.lang());
+  }
+
+  use(l: Lang) {
+    this.lang.set(l);
+    this.translate.use(l);
+    try { localStorage.setItem(Constants.LANGUAGE_KEY, l); } catch {}
+  }
+
+  private getInitial(): Lang {
+    try {
+      const stored = localStorage.getItem(Constants.LANGUAGE_KEY) as Lang | null;
+      if (stored === 'de' || stored === 'en') return stored;
+    } catch {}
+    const browser = (navigator.language || 'en').toLowerCase();
+    return browser.startsWith('de') ? 'de' : 'en';
+  }
+}