Merge pull request #63 from coderdojo-japan/fix/post-heading

記事ページにある見出しのレイアウトを修正

Author: mucho613

_layouts/post.html

@@ -3,7 +3,7 @@
 ---
 {% include navbar.html %}
 
-<h2 class="max-w-4xl mx-auto text-4xl text-center mb-2 mt-30 px-8 xl:mt-15">
+<h2 class="mx-auto text-4xl text-center mb-2 mt-30 px-4 sm:px-8 xl:mt-15">
   {{ page.title }}
   <span class="block mt-5 text-2xl">{{ page.subtitle | upcase }}</span>
 </h2>