If you need to use the scaling layout first have to put Display:flex, for compatibility also prefix Display:-webkit-display:flex, and other browser prefixes, but my native chrome test has no need to prefix, in fact, these are OK, The key mobile does not support this property, mobile support or the old version of the Display:-webki-box; but for learning, it doesn't support it, learn to say it, not to mention that Chrome has already put the flex prefix, which shows that Flex is still somewhat stable.
Here are a list of some of the properties that CSS uses with Flex
Display mode
Flex-direction setting the direction of the Flex model
Justify-content Setting the alignment of the horizontal direction
Align-items Setting the alignment of the vertical direction
Flex-wrap whether the line is wrapped
Align-content setting the alignment after line wrapping
Flex-flow Shorthand flex-direction and Flex-wrap
Order specified in sequence
Align-self the aligned item properties of the overlay container
FLEX Specifies length
CSS3 Flex Layout Flexible Learning Notes