References Address: https://www.cnblogs.com/qcloud1001/p/9848619.html
Priorities:
The elastic properties of the container
Acting on the cross shaft
- align-items: acting on a single line
- align-content: multi-line work, the container must be opened before they can wrap.
Acting on the spindle
- justify-content: the spindle is disposed in alignment
Common property conform
flex = flex-grow + flex-shrink + flex-basis
