flex 布局

item-1

item-2

item-3

item-4

item-5

flex-direction

rowrow-reversecolumncolumn-reverse

flex-wrap

nowrapwrapwrap-reverse

justify-content

flex-startflex-endcenterspace-betweenspace-aroundspace-evenly

align-items

flex-startflex-endcenterbaselinestretch

align-content

flex-startflex-endcenterspace-betweenspace-aroundstretch