Support the mathematical expressions (#55).

_posts/2019-08-08-text-and-typography.md

@@ -4,9 +4,10 @@ author: Cotes Chung
 date: 2019-08-08 11:33:00 +0800
 categories: [Blogging, Demo]
 tags: [typography]
+math: true
 ---
 
-This Jekyll template totally compatible with Markdown syntax. Now, let's take a look for the text and typography in this theme.
+This Jekyll template totally compatible with Markdown syntax. Now, let's take a look for the text and typography in here.
 
 ## Titles
 
@@ -49,7 +50,7 @@ Fluttering and dancing in the breeze.
 
 ## Link
 
-[http://127.0.0.1:4000](http://127.0.0.1:4000)
+<http://127.0.0.1:4000>
 
 
 ## Footnote
@@ -66,6 +67,15 @@ Click the hook will locate the footnote[^footnote].
 
 This is an example of `Inline Code`.
 
+## Mathematics
+
+The mathematics powered by [**MathJax**](https://www.mathjax.org/):
+
+$$ \sum_{n=1}^\infty 1/n^2 = \frac{\pi^2}{6} $$
+
+When \\(a \ne 0\\), there are two solutions to \\(ax^2 + bx + c = 0\\) and they are
+
+$$ x = {-b \pm \sqrt{b^2-4ac} \over 2a} $$
 
 ## Code Snippet
 

_posts/2019-08-08-write-a-new-post.md

@@ -113,6 +113,17 @@ comments: false
 ```
 
 
+## Mathematics
+
+For website performance reasons, the mathematical feature won't be loaded by default. But it can be enabled by:
+
+```yaml
+---
+math: true
+---
+```
+
+
 ## Code Block
 
 Markdown symbols <code class="highlighter-rouge">```</code> can easily create a code block as following examples.
@@ -136,7 +147,7 @@ items:
       quantity:  4
 ```
 
-#### Liquid codes
+#### Liquid Codes
 
 If you want to display the **Liquid** snippet, surround the liquid code with `{% raw %}{%{% endraw %} raw {%raw%}%}{%endraw%}` and `{% raw %}{%{% endraw %} endraw {%raw%}%}{%endraw%}` .
 
@@ -148,6 +159,8 @@ If you want to display the **Liquid** snippet, surround the liquid code with `{%
 ```
 {% endraw %}
 
+
 ## Learn More
+
 For more knowledge about Jekyll posts, visit the [Jekyll Docs: Posts](https://jekyllrb.com/docs/posts/).