feat: added navigation link in view

QuizApp/CategorySelectionView.swift

@@ -9,31 +9,58 @@ import SwiftUI
 
 struct CategorySelectionView: View {
     @ObservedObject var viewModel = ViewModel()
-    @State private var selectedCategory: String? = nil
     
     var body: some View {
-        if viewModel.selectedCategory != nil && !viewModel.questions.isEmpty {
-            ContentView(viewModel: viewModel)
-        } else {
-            VStack(spacing: 20) {
-                Text("Wähle eine Kategorie")
-                    .font(.largeTitle)
+        NavigationStack {
+            VStack(spacing: 24) {
+                // Minimaler Header
+                Text("Quiz Kategorien")
+                    .font(.title)
+                    .fontWeight(.bold)
+                    .padding(.top)
                 
+                // Liste der Kategorien
+                VStack(spacing: 12) {
                     ForEach(viewModel.availableCategories, id: \.self) { category in
-                    Button(action: {
+                        NavigationLink(destination: ContentView(viewModel: viewModel)
+                            .onAppear {
                                 viewModel.loadQuestions(for: category)
-                        selectedCategory = category
                             }) {
-                        Text(category)
+                            HStack {
+                                Image(systemName: "play.circle.fill")
+                                    .foregroundColor(.blue)
                                     .font(.title2)
+                                
+                                Text(category)
+                                    .font(.headline)
+                                    .foregroundColor(.primary)
+                                
+                                Spacer()
+                                
+                                Image(systemName: "chevron.right")
+                                    .foregroundColor(.secondary)
+                                    .font(.caption)
+                            }
                             .padding()
-                            .frame(maxWidth: 300)
-                            .background(Color.blue)
-                            .foregroundColor(.white)
-                            .cornerRadius(12)
-                    }
-                }
-            }
+                            .background(
+                                RoundedRectangle(cornerRadius: 12)
+                                    .fill(Color(.systemGray6))
+                                    .overlay(
+                                        RoundedRectangle(cornerRadius: 12)
+                                            .stroke(Color(.systemGray4), lineWidth: 1)
+                                    )
+                            )
+                        }
+                        .buttonStyle(PlainButtonStyle())
+                    }
+                }
+                .padding(.horizontal)
+                
+                Spacer()
+            }
+            .background(Color.white)
+            .navigationBarHidden(true)
         }
     }
 }
+