水平的主軸row，垂直的交叉軸column
- 主軸方向：flex-direction: row | row-reverse | column | column-reverse
- 主軸對齊方式：justify-content: flex-start | center | flex-end | space-between(間隔排列) | spae-around(項(xiàng)目兩側(cè)的間隔相等)
- 當(dāng)屬性定義多根軸線的對其方式，如果只有一根軸線，該屬性不起作用：align-content: flex-start | flex-end | center | space-around | space-between
- 垂直軸對齊方式：align-items: flex-start | center | flex-end | stretch(默認(rèn)值 項(xiàng)目未設(shè)置高度或者auto則占滿整個容器的高度) | baseline(項(xiàng)目的第一行文字基線對齊)
- 允許單個項(xiàng)目與其他項(xiàng)目有不一樣的對齊方式,可覆蓋align-items：aligin-self: flex-start | center | flex-end | stretch(默認(rèn)值 項(xiàng)目未設(shè)置高度或者auto則占滿整個容器的高度) | baseline(項(xiàng)目的第一行文字基線對齊)
- 換行方式：flex-wrap: nowrap | wrap | wrap-reverse
- flex-flow: flex-direction flex-wrap
- 當(dāng)屬性定義了在非配多余空間之前會根據(jù)這個屬性，計算主軸是否有多余空間 flex-basis：
- flex-grow:
- flex-shrink:
當(dāng)元素設(shè)置為flex布局之后，子元素的float，clear，vertical-align將會失效
容器上屬性：
display: flex;
flex-direction: row | row-reserve | column | column-reserve
flex-wrap: nowrap | wrap | wrap-reserve
flex-flow: flex-direction , flex-wrap
justify-content: flex-start | flex-end | center | space-between | space-around
align-items: flex-start | flex-end | center | baseline | stretch
align-content: flex-start | flex-end | center | stretch | space-between | space-around項(xiàng)目上屬性：
order: <number> 排列順序，數(shù)值越小排列越前，默認(rèn)值0
flex-grow: <number> 當(dāng)為1時，平分剩余空間，等列排布， 默認(rèn)值0
flex-shrink: <number> 當(dāng)有為0時，空間不夠不會縮小，其余縮小，默認(rèn)值1
flex-basis: width的屬性寫法，項(xiàng)目的大小，當(dāng)空間不足時會縮小，按照flex-shrink的縮小規(guī)則
flex: flex-grow , flex-shrink , flex-basis
align-self: flex-start | flex-end | center | stretch | baseline
