:sparkles: first touch of responsive

frontend/src/App.vue

 #app > .w-app > main
     position: relative
     top: 50px
+    max-width: 960px
+    width:100%
 </style>

frontend/src/components/MainNav.vue

     name: 'MainNav',
 }
 </script>
+
+<style lang="sass">
+.w-toolbar
+    max-width: 960px
+    width:100%
+    margin: auto
+</style>
+