add: folder structure for markdown content pages

src/layouts/BaseLayout.astro

@@ -8,7 +8,7 @@ import '../styles/main.scss'
 const { title, description, thumbnail, pageName } = Astro.props
 ---
 
-<!DOCTYPE html>
+<!doctype html>
 <html lang="en">
     <head>
         <meta charset="UTF-8" />
@@ -22,7 +22,7 @@ const { title, description, thumbnail, pageName } = Astro.props
 
         <title>{title}</title>
     </head>
-    <body class:list={['page-' + (pageName ?? 'unknown')]}>
+    <body class:list={Array.isArray(pageName) ? pageName : [pageName]}>
         <slot />
     </body>
 </html>