Mix + Tailwind + Multiple Tailwind Configs

I have setup a mix file that I have compiling 4 different Tailwind config files (3 different sites + 1 backend). I have a basic index page setup for the three sites and when I run npm run dev it compiles but it doesn't pick up any of the tailwind classes in my views.

webpack.mix.js

const mix = require('laravel-mix')
require('mix-tailwindcss')

mix.js('resources/js/site1.js', 'public/js')
       .sass('resources/scss/site1.scss', 'public/css')
       .tailwind('./tailwind.site1.config.js')
       .sourceMaps();

mix.js('resources/js/site2.js', 'public/js')
       .sass('resources/scss/site2.scss', 'public/css')
       .tailwind('./tailwind.site2.config.js')
       .sourceMaps();

tailwind.site1.config.js

const defaultTheme = require('tailwindcss/defaultTheme')

module.exports = {
   content: [
		'resources/views/site/site1/**/*.blade.php',
		'resources/js/site1.js',
		'resources/js/site1/**/*.js'
	]
};