Just sharing a few ways of creating build profiles for web projects.
2. Cheerio Grunt Plugin
Use cheerio to manipulate the html file(s) to load dev vs. prod files and resources. Create a Grunt task that finds the CSS and Script tags and replace the href with the appropriate files.
3. Jade Templating Engine
Use jade to generate the html file(s) that load dev vs. prod files and resources. Use grunt-contrib-jade to pass in data to generate the files for the appropriate environment.