refactor: update configuration files to use ES module syntax and integrate Tailwind CSS

src/assets/main.css

@@ -1,7 +1,5 @@
-@import './base.css';
-@tailwind base;
-@tailwind components;
-@tailwind utilities;
+@import "./base.css" layer(base);
+@import "tailwindcss";
 
 #app {
   width: 100%;