Update project configuration and dependencies: add Tailwind CSS support, update .gitignore, and enhance TypeScript configuration.

astro.config.mjs

@@ -1,5 +1,10 @@
 // @ts-check
 import { defineConfig } from 'astro/config';
+import tailwindcss from '@tailwindcss/vite';
 
 // https://astro.build/config
-export default defineConfig({});
+export default defineConfig({
+  vite: {
+    plugins: [tailwindcss()],
+  },
+});