2-1. flex-direction屬性
.flex-container {
flex-direction: row | row-reverse | column | column-reverse;
}
2-2. 其他書寫方向
writing-mode
direction
2-3. 彈性行折行
flex-wrap: nowrap|wrap|wrap-reverse|initial|inherit;
2-4. 定義彈性流動
flex-flow: flex-direction || flex-wrap
2-5. flex-wrap