Improve local datetime display

- Protect author's location privacy
- Reduce locale configuration parameters

_layouts/tag.html

@@ -12,13 +12,13 @@ layout: page
     <span class="lead text-muted pl-2">{{ page.posts | size }}</span>
   </h1>
   <ul class="post-content pl-0">
-    {% assign post_df = site.data.locales[lang].date_format.post.long %}
-
     {% for post in page.posts %}
     <li class="d-flex justify-content-between pl-md-3 pr-md-3">
       <a href="{{ post.url | relative_url }}">{{ post.title }}</a>
       <span class="dash flex-grow-1"></span>
-      <span class="text-muted small">{{ post.date | date: post_df }}</span>
+      <span class="text-muted small" data-ts="{{ post.date | date: '%s' }}" data-df="ll">
+        {{ post.date | date: '%Y-%m-%d' }}
+      </span>
     </li>
     {% endfor %}
   </ul>