kramdown syntax
对于一些block元素, 需要前面有空行(这和传统markdown不同), 例如header(## header), list, fenced code block, math code.
Header5
Header4
Header3
Header2
Header2
Header1
Header1
This is some text1. Other text2.
a blog
若要启用数学公式支持，需要引入MathJax.js
<script src="http://cdn.mathjax.org/mathjax/latest/MathJax.js?config=TeX-AMS-MML_HTMLorMML"></script>可以在_layouts/default.html的body结束标签之前添加，离线安装有点麻烦，具体可参考链接。
$$
\begin{align*}
& \phi(x,y) = \phi \left(\sum_{i=1}^n x_ie_i, \sum_{j=1}^n y_je_j \right)
= \sum_{i=1}^n \sum_{j=1}^n x_i y_j \phi(e_i, e_j) = \\
& (x_1, \ldots, x_n) \left( \begin{array}{ccc}
\phi(e_1, e_1) & \cdots & \phi(e_1, e_n) \\
\vdots & \ddots & \vdots \\
\phi(e_n, e_1) & \cdots & \phi(e_n, e_n)
\end{array} \right)
\left( \begin{array}{c}
y_1 \\
\vdots \\
y_n
\end{array} \right)
\end{align*}
$$This is inline