Improve CSS syntax highlighting (#1367)

Fixes #1340
Fixes #1250

This PR is intended to improve syntax highlighting for CSS. Currently
things like `@plugin` are not always handled right, declarations inside
`@theme` may be incorrectly tokenized — or even not at all, etc…

**Proper nesting support will come in a separate PR**

The best way to test this is to:
- Clone the repo
- Run the extension in the dev host
- New file in the Tailwind CSS language mode
- Toss in a bunch of CSS (can look at the tests for lots of stuff)

Author: thecrypticace

.github/workflows/ci.yml

@@ -26,6 +26,18 @@ jobs:
       - name: Install dependencies
         run: pnpm install
 
+      - name: Run syntax tests
+        run: |
+          cd packages/tailwindcss-language-syntax &&
+          pnpm run build &&
+          pnpm run test
+
+      - name: Run service tests
+        run: |
+          cd packages/tailwindcss-language-service &&
+          pnpm run build &&
+          pnpm run test
+
       - name: Run tests
         run: |
           cd packages/tailwindcss-language-server &&

packages/tailwindcss-language-service/scripts/build.mjs

@@ -3,8 +3,9 @@ import { spawnSync } from 'node:child_process'
 import esbuild from 'esbuild'
 import minimist from 'minimist'
 import { nodeExternalsPlugin } from 'esbuild-node-externals'
+import { fileURLToPath } from 'node:url'
 
-const __dirname = new URL('.', import.meta.url).pathname
+const __dirname = path.dirname(fileURLToPath(import.meta.url))
 
 const args = minimist(process.argv.slice(2), {
   boolean: ['watch', 'minify'],
@@ -30,7 +31,13 @@ let build = await esbuild.context({
           // Call the tsc command to generate the types
           spawnSync(
             'tsc',
-            ['-p', path.resolve(__dirname, './tsconfig.build.json'), '--emitDeclarationOnly', '--outDir', path.resolve(__dirname, '../dist')],
+            [
+              '-p',
+              path.resolve(__dirname, './tsconfig.build.json'),
+              '--emitDeclarationOnly',
+              '--outDir',
+              path.resolve(__dirname, '../dist'),
+            ],
             {
               stdio: 'inherit',
             },

packages/tailwindcss-language-syntax/package.json

@@ -0,0 +1,16 @@
+{
+  "name": "@tailwindcss/language-syntax",
+  "version": "0.0.0",
+  "private": true,
+  "scripts": {
+    "test": "vitest",
+    "build": " "
+  },
+  "devDependencies": {
+    "@types/node": "^18.19.33",
+    "dedent": "^1.5.3",
+    "vitest": "^3.1.4",
+    "vscode-oniguruma": "^2.0.1",
+    "vscode-textmate": "^9.2.0"
+  }
+}