feat: migrate workspace to Tailwind CSS v4 (#377)

* feat: migrate workspace to Tailwind CSS v4

* refactor: move Tailwind v4 setup to CSS directives

packages/email-editor/package.json

@@ -18,17 +18,17 @@
   "author": "",
   "license": "ISC",
   "devDependencies": {
+    "@tailwindcss/postcss": "^4.1.0",
     "@types/eslint": "^9.6.1",
     "@types/react": "^19.1.2",
     "@usesend/eslint-config": "workspace:*",
-    "@usesend/tailwind-config": "workspace:*",
     "@usesend/typescript-config": "workspace:*",
     "@usesend/ui": "workspace:*",
     "postcss": "^8.5.3",
     "prettier": "^3.5.3",
     "prettier-plugin-tailwindcss": "^0.6.11",
     "react": "^19.1.0",
-    "tailwindcss": "^3.4.1",
+    "tailwindcss": "^4.1.0",
     "tsup": "^8.4.0",
     "typescript": "^5.8.3"
   },

packages/email-editor/postcss.config.cjs

@@ -1,6 +1,6 @@
 const config = {
   plugins: {
-    tailwindcss: {},
+    "@tailwindcss/postcss": {},
   },
 };
 

packages/email-editor/src/styles/index.css

@@ -1,3 +1,5 @@
+@reference "tailwindcss";
+
 .unsend-editor .unsend-prose p:where([class~="text-sm"]) {
   font-size: 16px;
 }

packages/email-editor/tailwind.config.ts

@@ -1,7 +0,0 @@
-import { type Config } from "tailwindcss";
-import sharedConfig from "@usesend/tailwind-config/tailwind.config";
-
-export default {
-  ...sharedConfig,
-  content: ["./src/**/*.tsx", "./src/**/*.ts"],
-} satisfies Config;