flex

http://www.w3.org/html/ig/zh/wiki/Css3-flexbox

https://developer.mozilla.org/zh-CN/docs/CSS/CSS_Reference

http://www.poluoluo.com/jzxy/201208/173719.html

http://school.cnd8.com/css/jiaocheng/85692.htm

http://sd.csdn.net/index.php?c=page&m=subject&name=article&arcid=2808582