当flex items的大小超过了flex container时， 各个flex item的压缩比例，下面有个不错的教程，大家可以参考下

在CSS3 Flexbox中flex-shrink属性定义为: This component sets ‘flex-shrink’ longhand and specifies the flex shrink factor, which determines how much the flex item will shrink relative to the rest of the flex items in the flex container when negative free spa