Combine SASS/SCSS and CSS in a bundle

I would like to figure out how I can combine the transpiled SCSS>CSS in the same bundle as the rest of the CSS.

My current setup results in the error:
execute of template failed: template: partials/head/stylesheets.html:24:37: executing "partials/head/stylesheets.html" at <resources.Concat>: error calling Concat: expected slice of Resource objects, received []interface {} instead

Other attempts resulted in the following error:
error calling toCSS: runtime error: invalid memory address or nil pointer