chore: upgrade to Tailwind 4

frontend/package.json

@@ -26,13 +26,12 @@
     "eslint-config-prettier": "^9.1.0",
     "eslint-plugin-svelte": "^2.46.0",
     "globals": "^15.11.0",
-    "postcss": "^8.4.47",
     "prettier": "^3.3.3",
     "prettier-plugin-svelte": "^3.2.7",
     "prettier-plugin-tailwindcss": "^0.6.8",
     "svelte": "^5.0.5",
     "svelte-check": "^4.0.5",
-    "tailwindcss": "^3.4.14",
+    "tailwindcss": "^4.0.0",
     "tslib": "^2.8.0",
     "typescript": "^5.6.3",
     "typescript-eslint": "^8.11.0",
@@ -41,6 +40,7 @@
   "type": "module",
   "dependencies": {
     "@simplewebauthn/browser": "^10.0.0",
+    "@tailwindcss/vite": "^4.0.0",
     "axios": "^1.7.7",
     "bits-ui": "^0.21.16",
     "clsx": "^2.1.1",

frontend/postcss.config.js

@@ -1,6 +0,0 @@
-export default {
-	plugins: {
-		tailwindcss: {},
-		autoprefixer: {}
-	}
-};

frontend/src/app.css

@@ -1,6 +1,6 @@
-@tailwind base;
+@import "tailwindcss";
-@tailwind components;
+
-@tailwind utilities;
+@config '../tailwind.config.ts';
 
 @layer base {
 	:root {

frontend/vite.config.ts

@@ -1,6 +1,7 @@
 import { sveltekit } from '@sveltejs/kit/vite';
+import tailwindcss from '@tailwindcss/vite';
 import { defineConfig } from 'vite';
 
 export default defineConfig({
-	plugins: [sveltekit()]
+	plugins: [sveltekit(), tailwindcss()]
 });