change language property

_layouts/post.html

@@ -1,7 +1,7 @@
 ---
 layout: default
 ---
-<div class='post {% if page.fa %}fa-post{% endif %}'>
+<div class='post lang-{% if page.lang %}{{ page.lang }}{% else %}en{% endif %}'>
 
   <div class="post-header">
     <h1 class="post-title">{{ page.title }}</h1>

_sass/_layout.scss

@@ -127,7 +127,7 @@ strong {
   }
 }
 
-.fa-post {
+.lang-fa {
   font-family: $base-font-family;
   direction: rtl !important;
   .post-content {

index.html

@@ -6,7 +6,7 @@ layout: default
 
   <ul class="post-list">
     {% for post in site.posts %}
-      <li class='{% if post.fa %}fa-post{% endif %}'>
+      <li class='lang-{% if post.lang %}{{ post.lang }}{% else %}en{% endif %}'>
         <h2>
           <a class="post-link" href="{{ post.url | prepend: site.baseurl }}">{{ post.title }}</a>