Can someone explain how sass is compiling here??

main.js

import $ from "jquery";

import '../scss/main.scss';

// jQuery HoverIntent
import hoverintent from 'hoverintent';
window.hoverintent = hoverintent

// Alpine JS
import Alpine from 'alpinejs'
window.Alpine = Alpine

Alpine.plugin(collapse);
Alpine.plugin(focus);
Alpine.start();

// Modules
// import exampleModule from './modules/example';

window.addEventListener("load", () => {
	// exampleModule();
});

package.json

{
  "name": "hc_wp_theme",
  "version": "1.0.0",
  "main": "assets/js/main.js",
  "repository": "https://github.com/happycog/wordpress-bootstrap",
  "author": "Happy Cog / Chris Lagasse <chris@happycog.com",
  "license": "MIT",
  "private": true,
  "scripts": {
    "build": "vite build",
    "dev": "vite build --watch"
  },
  "devDependencies": {
    "autoprefixer": "^10.4.13",
    "postcss": "^8.4.20",
    "postcss-import": "^14.1.0",
    "postcss-nested": "^6.0.1",
    "vite": "^4.1.1"
  },
  "dependencies": {
    "@alpinejs/collapse": "^3.12.2",
    "alpinejs": "^3.12.0",
    "hoverintent": "^2.2.1",
    "jquery": "^3.6.3"
  }
}

postcss.config.js

module.exports = {
  plugins: [
    require('postcss-nested'),
    require('autoprefixer'),
  ]
}

vite.config.js

export default ({ command }) => ({
	base: "/wp-content/themes/kcrw-giveaways/assets/dist/",
	build: {
		assetsDir: "",
		emptyOutDir: true,
		manifest: false,
		outDir: "./assets/dist/",
		rollupOptions: {
			input: {
				main: "./assets/src/js/main.js",
			},
			output: {
        entryFileNames: `js/[name].js`,
        chunkFileNames: `js/[name].js`,
        assetFileNames: (assetInfo) => {
					let folder = 'static/';
          let extType = assetInfo.name.split('.')[1];
          if (/ttf|woff|woff2/i.test(extType)) {
						folder = 'fonts/';
					} else if (/css/i.test(extType)) {
            folder = 'css/';
          }

					return `${folder}[name].[ext]`;
				}
      }
		}
	}
});

More information:

I wanted to strip out tailwind and add sass, and while doing so, I was having a lot of issues (because I also removed postcss). However, there's nothing here that would tell postcss to properly handle (or even TRY to handle) sass, but it seems to take it into account when processing.

This... wasn't expected. I do not understand why.