tested with example

app/app.css

@@ -1,7 +1,34 @@
 @import '@nativescript/theme/css/core.css';
 @import '@nativescript/theme/css/default.css';
 
-/* Label {
-  font-size: 23;
-  color: red;
-} */
+
+/* Place any CSS rules you want to apply on both iOS and Android here.
+This is where the vast majority of your CSS code goes. */
+
+/* applied when device is in light mode */
+.ns-light .bg-primary {
+  background-color: #fdfdfd;
+}
+.ns-light .bg-secondary {
+  background-color: #ffffff;
+}
+.ns-light.text-primary {
+  color: #444;
+}
+.ns-light.text-secondary {
+  color: #777;
+}
+
+/* applied when device is in dark mode */
+.ns-dark .bg-primary {
+  background-color: #212121;
+}
+.ns-dark .bg-secondary {
+  background-color: #383838;
+}
+.ns-dark .text-primary {
+  color: #eee;
+}
+.ns-dark .text-secondary {
+  color: #ccc;
+}

elm-native-js/Native/Constants.res

@@ -144,6 +144,7 @@ let textBase: array<string> =
     paddings,
     [
       "fontSize",
+      "fontWeight",
       "formattedText",
       "letterSpacing",
       "lineHeight",
@@ -314,6 +315,7 @@ let commonTextBase =
     "autofillType",
     "editable",
     "fontSize",
+    "fontWeight",
     "formattedText",
     "hint",
     "keyboardType",
@@ -376,7 +378,12 @@ let actionItem =
 let listView =
   [
     view,
-    ["itemTemplateSelector", "iosEstimatedRowHeight", "rowHeight", "separatorColor"]->Belt.Array.map(dashed),
+    [
+      "itemTemplateSelector",
+      "iosEstimatedRowHeight",
+      "rowHeight",
+      "separatorColor",
+    ]->Belt.Array.map(dashed),
   ]->Belt.Array.concatMany
 
 // Js.log("****************************")

elm-native/src/Native/Attributes.elm

@@ -9,6 +9,11 @@ fontSize : String -> Attribute msg
 fontSize =
     attribute "font-size"
 
+fontWeight : String -> Attribute msg
+fontWeight =
+    attribute "font-weight"
+
+
 
 fontStyle : String -> Attribute msg
 fontStyle =
@@ -1153,3 +1158,5 @@ separatorColor =
 itemTemplateSelector : String -> Attribute msg
 itemTemplateSelector =
     attribute "item-template-selector"
+
+

elm-native/src/Native/Event.elm

@@ -26,13 +26,13 @@ on eventName =
 
 {-| Method values are kept under {custom: {[methodName]: value}}
 example:
-  Event.onEventWithMethodCalls "touch"
-    [ "getX", "getY" ]
-    (D.map2 Tuple.pair
-      (D.at [ "custom", "getX"] D.float)
-      (D.at [ "custom", "getY"] D.float)
-    |> D.map Msg
-    )
+Event.onEventWithMethodCalls "touch"
+[ "getX", "getY" ]
+(D.map2 Tuple.pair
+(D.at [ "custom", "getX"] D.float)
+(D.at [ "custom", "getY"] D.float)
+|> D.map Msg
+)
 -}
 onEventWithMethodCalls : String -> List String -> D.Decoder msg -> Attribute msg
 onEventWithMethodCalls eventName methods =
@@ -94,6 +94,6 @@ onSelectedIndexChange msg =
     on "selectedIndexChange" (D.field "value" D.int |> D.map msg)
 
 
-onItemTap : D.Decoder msg -> Attribute msg
-onItemTap itemDecoder =
-    on "itemTap" (D.field "item" itemDecoder)
+onItemTap : (Int -> msg) -> Attribute msg
+onItemTap msg =
+    on "itemTap" (D.field "index" D.int |> D.map msg)

elm-native/src/Native/Frame.elm

@@ -1,10 +1,10 @@
-module Native.Frame exposing (Model, frame)
+module Native.Frame exposing (Model, back, frame, init, current)
 
 import Html exposing (Attribute, Html)
 
 
-type alias Model a page =
-    { a | current : page, next : Maybe page, history : List page }
+type alias Model page =
+    { current : page, history : List page }
 
 
 cons : List a -> a -> List a
@@ -12,12 +12,12 @@ cons acc x =
     x :: acc
 
 
-frame : Model a page -> List ( page, Model a page -> Html msg ) -> List (Attribute msg) -> Html msg
-frame model pages attrs =
+frame : Model page -> model -> List ( page, model -> Html msg ) -> List (Attribute msg) -> Html msg
+frame model appModel pages attrs =
     let
         children =
             pages
-                |> getPage model.current model
+                |> getPage model.current appModel
                 |> Maybe.map List.singleton
                 |> Maybe.withDefault []
 
@@ -26,24 +26,23 @@ frame model pages attrs =
                 |> List.foldl
                     (\old acc ->
                         pages
-                            |> getPage old model
+                            |> getPage old appModel
                             |> Maybe.map (cons acc)
                             |> Maybe.withDefault acc
                     )
                     children
 
-        _ =
-            Debug.log "Childenr" (List.length history)
+        -- _ =
+        --     Debug.log "Childenr" (List.length history)
     in
     (Html.node "ns-frame"
         attrs
-        (history
+        history
      -- model.history
      -- |> List.foldl
      --     (\next acc ->
      --     )
      --     []
-        )
      -- ([ pages
      --     |> getPage model.current model
      --  , model.next
@@ -92,10 +91,33 @@ findInList target toItem acc ls =
                 findInList target toItem acc r
 
 
+init : page -> Model page
+init currentPage =
+    { current = currentPage
+    , history = []
+    }
 
--- root : Frame msg -> Html msg
--- root (Frame e) =
---     e
--- asElement : Frame msg -> Html msg
--- asElement =
---     root
+
+back : Bool -> Model page -> Model page
+back bool model =
+    if not bool then
+        model
+
+    else
+        case model.history of
+            [] ->
+                model
+
+            cur :: [] ->
+                { model | history = [], current = cur }
+
+            _ :: cur :: rest ->
+                { model | history = rest, current = cur }
+
+
+current : page -> Model page -> Model page
+current page model =
+    { model
+        | history = model.current :: model.history
+        , current = page
+    }