参考:
CSS3 弹性盒子(Flex Box)http://www.runoob.com/css3/css3-flexbox.html
http://www.runoob.com/css3/css3-flexbox.htmlhttp://www.runoob.com/w3cnote/flex-grammar.html
彻底弄懂css3的flex弹性盒模型https://www.cnblogs.com/qq9694526/p/5713698.html
Flex 布局教程:语法篇http://www.ruanyifeng.com/blog/2015/07/flex-grammar.html?utm_source=tuicoolDEMO:http://static.vgee.cn/static/index.html
http://vgee.cn/(前端网站)
Webkit Flex伸缩盒模型属性备忘https://www.cnblogs.com/wangjiajun/p/3994263.html