Flexbox

1. flex- container = Parent

display : inline-block을 display : flex로 변경하기

display: flex 와 inline-flex 차이 명확히 

flex-direction : row(default) vs column // row-reverse, column-reverse

flex-wrap : nowrap(default) vs wrap...

2. Main Axis vs. Cross Axis

flex-direction : row(default) vs column // row-reverse, column-reverse

3. Flex Items = Children

align-items : stretch(default), flex-start, ...   

align-content 

justify-content