容器属性
display: flex | inline-flex
flex-direction: row | row-reverse | column | column-reverse
flex-wrap: nowrap | wrap | wrap-reverse
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 | space-between | space-around | stretch;
flex-flow: <flex-direction> || <flex-wrap>
子元素
<integer><br><number>
flex-grow: <number>; /* default 0 */
flex-shrink: <number>; /* default 1 */
flex-basis: <length> | auto; /* default auto */
flex: none | [ <'flex-grow'> <'flex-shrink'>? || <'flex-basis'> ] /*default 0 1 auto*/ 优先使用此值
align-self: flex-start | flex-end | center | baseline | stretch
