Añadido html y css de la navegación, faltan las rutas

angular/RestClient/src/app/navigation/navigation.component.css

+nav {
+    background-color: #333;
+    color: white;
+    padding: 1em;
+  }
+  
+  ul {
+    list-style: none;
+    padding: 0;
+    display: flex;
+  }
+  
+  li {
+    margin-right: 20px;
+  }
+  
+  a {
+    color: white;
+    text-decoration: none;
+  }
+  
+  a:hover {
+    text-decoration: underline;
+  }
+  
+  .active {
+    font-weight: bold;
+  }
+  
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