build: remove tailwindcss but add to docs

docs/astro.config.mjs

@@ -1,14 +1,14 @@
 import { defineConfig } from "astro/config";
 import starlight from "@astrojs/starlight";
 
+import tailwind from "@astrojs/tailwind";
+
 // https://astro.build/config
 export default defineConfig({
-    integrations: [
-        starlight({
-            title: "File Converter Tool",
-            social: {
-                github: "https://github.com/rzmk/fct",
-            },
-        }),
-    ],
-});
+  integrations: [starlight({
+    title: "File Converter Tool",
+    social: {
+      github: "https://github.com/rzmk/fct"
+    }
+  }), tailwind()]
+});