{{ $processedResources := slice }}
{{ range $r := resources.Match "css/*.css" }}
  {{
    $processedResources = append
      (resources.Get $r | resources.ExecuteAsTemplate $r (dict "Page" $))
      $processedResources
  }}
{{ end }}

{{ $css := $processedResources | resources.Concat "css/base.css" }}
{{ return $css }}