The package's stylesheet, as a string.

The Elm package registry only distributes src/, elm.json, README.md and LICENSE, so cally.css from the repository root cannot reach you through elm install. This module carries the same bytes, so the default look is available to anything that can put CSS on a page:

import Cally.Css
import Html exposing (Html, node, text)


styles : Html msg
styles =
    node "style" [] [ text Cally.Css.stylesheet ]

Or write it out at build time, from elm-review, a codegen step or a scratch Platform.worker that prints it, and serve it as a real .css file.

The stylesheet is plain light-DOM CSS: it targets the element names the pickers render (calendar-date, calendar-month, ...) and their part attributes, so it is global and only needs to appear on the page once.