Struggling to apply CSS styles to Elm application

Question

I’ve been having issues figuring out the best approach to style Elm 19 applications. Here is what I’ve been trying but to no avail:

module Main exposing (..)

import Browser
import Html exposing (..)
import Html.Attributes exposing (..)
import Html.Styled.Attributes exposing (css)
import List exposing (..)
import Css exposing (..)

type alias Model = List Status
type alias Status = { status : String }


main =
    Browser.element
        { init = init
        , view = view
        , update = update
        , subscriptions = subscriptions
        }


-- Note: I removed the init, update, and subscriptions functions from this code snippet as it does not seem like they were relevant to my question.


view : Model -> Html Msg
view model =
    main_ 
        [ css
        [ color (hex "ffffff")
        , backgroundColor (hex "000000")
        , Css.height (vh 100) ]
        ]
        [ h1
            [ css [ margin (px 0) ] ]
            [ text "The title of my app" ]
        , input [ value ""] []
        ]

The compiler points out that the problem I’m having in main_ is the following:

<!-- language: lang-none -->
This argument is a list of type:

    List #(Html.Styled.Attribute msg)#

But `main_` needs the 1st argument to be:

    List #(Attribute msg)#

Here is the elm.json file:

{
    "type": "application",
    "source-directories": [
        "src"
    ],
    "elm-version": "0.19.1",
    "dependencies": {
        "direct": {
            "elm/browser": "1.0.2",
            "elm/core": "1.0.5",
            "elm/html": "1.0.0",
            "elm/time": "1.0.0",
            "ianmackenzie/elm-units": "2.9.0",
            "justinmimbs/date": "4.0.1",
            "rtfeldman/elm-css": "18.0.0"
        },
        "indirect": {
            "elm/json": "1.1.3",
            "elm/parser": "1.1.0",
            "elm/url": "1.0.0",
            "elm/virtual-dom": "1.0.3",
            "robinheghan/murmur3": "1.0.0",
            "rtfeldman/elm-hex": "1.0.0"
        }
    },
    "test-dependencies": {
        "direct": {},
        "indirect": {}
    }
}

I suspect that I might be using an old version of elm-css or something along these lines but I'm having a hard time understanding what's not working here for me.

Answer 1

In order to use elm-css you need to have a conversion from Html.Styled.Html to Html.Html using Html.Styled.toUnstyled. This means you need to have import Html.Styled exposing (..) instead of import Html exposing (..)

This means that main_ will be Html.Syled.main_ instead of Html.main_ (as it is right now).

You could then add at the end of your view code |> Html.Styled.toUnstyled and everything should work out fine.