anchor.diff:  %% Public API
   %% ===================================================================
   
  +
   compile(Config, _AppFile) ->
       Options = options(Config),
  +    DocRoot = option(doc_root, Options),
  +    Stylesheets = option(stylesheets, Options),
  +    Targets = [normalize_path(Stylesheet, DocRoot)
  +                || Stylesheet <- Stylesheets],
  +    process(Targets, Options).
  +
  +process([], _Options) ->
  +    ok;
  +process(Targets, Options) ->
       OutDir = option(out_dir, Options),
       DocRoot = option(doc_root, Options),
       Stylus = option(stylus_path, Options),
       case stylus_is_present(Stylus) of
           true ->
  -            Cmd = lists:flatten([Stylus, " -o ", OutDir, " ", DocRoot]),
  +            Cmd = lists:flatten([Stylus, " -o ", OutDir, " ",
  +                                 string:join(Targets, " ")]),
               ShOpts = [{use_stdout, false}, return_on_error],
               case rebar_utils:sh(Cmd, ShOpts) of
                   {ok, _} ->
  
positive.code:                     rebar_log:log(error, "Stylus asset processing failed failed:~n  ~p~n",
                             [Reason]),
                      rebar_utils:abort()
              end;
          false ->
              rebar_log:log(error,
                  "Bypassing stylesheet processing of ~s: stylus missing.~n", [DocRoot]),
  
negative.code: %%  out_dir: where to put preprocessed css files
  %%           "priv/www/stylesheets" by default
  %%
  %%  stylesheets: stylus files to compile
  %%           [] by default
  %%
  %% The default settings are the equivalent of:
  %%   {js_stylus, [
  %%               {stylus,       "/usr/local/bin/stylus"},
  %%               {doc_root,     "priv/assets/stylesheets"},
  %%               {out_dir,      "priv/www/stylesheets"}
  %%               {stylesheets,  []}
  %%              ]}.
  %%
  
  