You have to place icons, assets, images, etc which don’t need any further processing in priv/static folder.
Also don’t forget to add entry in the endpoint file if you are creating a top level folder:
# Serve at "/" the static files from "priv/static" directory.
#
# You should set gzip to true if you are running phx.digest
# when deploying your static files in production.
plug Plug.Static,
at: "/",
from: :my_app,
gzip: false,
only: ~w(assets favicons fonts images favicon.ico robots.txt)
If you want to process sass files, you can use Dart SaSS:
DartSass - An installer for sass
