概念
- 主轴
垂直轴
flex container
- flex item
默认行为
flex item的默认行为：
- 按行排列 flex-direction: row;
- 沿着主轴起始边界开始排列 justify-content: flex-start;
- 主轴方向不会膨胀，但会缩小 flex-grow: 0; flex-shrink: 1; flex-basis: auto;
- 垂直轴会膨胀填满空间 align-items: stretch;
- flex-basis: auto;
- flex-wrap: nowrap;
属性默认值，可选值
flex container
- flex-direction: row;
- flex-wrap: nowrap; (wrap)
- align-items: stretch; (flex-start, flex-end, center)
- justify-content: flex-start; (flex-end, center, space-around, space-between, space-evenly)
flex item
- flex-basis: auto; (inherit, initial, unset)
- flex: initial; (= 0 1 auto) (auto = 1 1 auto, none = 0 0 auto)