了解Flex布局

了解Flex布局。

https://www.cnblogs.com/dreamperson/p/9367008.html

http://www.ruanyifeng.com/blog/2015/07/flex-grammar.html

https://segmentfault.com/a/1190000008823763

https://zhuanlan.zhihu.com/p/25303493

https://juejin.im/post/58e3a5a0a0bb9f0069fc16bb

http://www.runoob.com/w3cnote/flex-grammar.html

https://www.jianshu.com/p/f82262002f8a