Remove PostCSS and move to Lightning CSS (hestiacp#3820)

* Remove postcss and move to lightningcss

* Remove non-standard `size` property

Author: imjuniper

build.js

@@ -4,9 +4,9 @@
 // Build JS and CSS using esbuild and PostCSS
 import { promises as fs } from 'node:fs';
 import path from 'node:path';
+import browserslist from 'browserslist';
 import esbuild from 'esbuild';
-import postcss from 'postcss';
-import postcssConfig from './postcss.config.js';
+import * as lightningcss from 'lightningcss';
 
 // Packages to build but exclude from bundle
 const externalPackages = ['chart.js/auto', 'alpinejs/dist/cdn.min.js'];
@@ -69,11 +69,39 @@ async function processCSS(inputFile, outputFile) {
 	try {
 		await ensureDir(path.dirname(outputFile));
 		const css = await fs.readFile(inputFile);
-		const result = await postcss(postcssConfig.plugins).process(css, {
-			from: inputFile,
-			to: outputFile,
+		const bundle = await lightningcss.bundleAsync({
+			filename: inputFile,
+			sourceMap: true,
+			code: Buffer.from(css),
+			minify: true,
+			targets: lightningcss.browserslistToTargets(browserslist()),
+			drafts: { customMedia: true, nesting: true },
+			visitor: {
+				Url: (node) => {
+					// Fix relative paths for webfonts
+					if (node.url.startsWith('../webfonts/')) {
+						return {
+							url: node.url.replace('../webfonts/', '/webfonts/'),
+							loc: node.loc,
+						};
+					}
+					return node;
+				},
+			},
+			resolver: {
+				resolve(specifier, from) {
+					if (!specifier.endsWith('.css')) {
+						specifier += '.css';
+					}
+					if (specifier.startsWith('node:')) {
+						return `node_modules/${specifier.replace('node:', '')}`;
+					}
+					return `${path.dirname(from)}/${specifier}`;
+				},
+			},
 		});
-		await fs.writeFile(outputFile, result.css);
+		await fs.writeFile(outputFile, bundle.code);
+		await fs.writeFile(`${outputFile}.map`, bundle.map);
 		console.log(`✅ CSS build completed for ${inputFile}`);
 	} catch (error) {
 		console.error(`❌ Error processing CSS for ${inputFile}:`, error);