update style

_layouts/post.html

@@ -21,4 +21,19 @@ layout: default
       <div class="fb-like" data-layout="button" data-action="like" data-size="large" data-show-faces="false" data-share="true"></div>
     </div>
   </article>
-</section>
+</section>
+
+<!-- MathJax -->
+<script type="text/x-mathjax-config">
+  MathJax.Hub.Config({
+    tex2jax: {
+    inlineMath: [['$','$'], ['\\(','\\)']],
+    displayMath: [['$$','$$'], ['\[','\]']],
+    processEscapes: false,
+    processEnvironments: false,
+    skipTags: ['script', 'noscript', 'style', 'textarea', 'pre', 'a']
+  }
+});
+</script>
+<script type="text/javascript" async src="https://cdnjs.cloudflare.com/ajax/libs/mathjax/2.7.2/MathJax.js?config=TeX-AMS_SVG">
+</script>