fix: use proper html tag

pages/blog.html

@@ -17,10 +17,10 @@
     <button id="theme-switcher"></button>
     <a class="account" href="/pages/account.html">Nalog</a>
   </header>
-  <div id="main">
+  <main>
     Ova stranica je trenutno u izradi...
     <img id="mesh" src="/img/mesh-light.svg">
-  </div>
+  </main>
   <footer>
     <div id="sections-menu">
       <a href="/pages/events.html">Događaji</a>