Clean Blog system

- Improved the blog posts
- Add a test to visit the blog index
- Add Tailwind Typography for the markdown blog posts

components/blog/post-body.tsx

@@ -9,7 +9,7 @@ type Properties = {
 const PostBody = ({ code }: Properties): JSX.Element => {
   const BlogPost = useMemo(() => getMDXComponent(code), [code]);
   return (
-    <div className="max-w-2xl mx-auto">
+    <div className="max-w-2xl mx-auto prose lg:prose-xl">
       <BlogPost />
     </div>
   );