Data transmission:
style:
display
up and down:
display:flex;
flex-direction{row|row-reverse|column|column-reverse}
row(默认)沿水平主轴由左向左排列，row-reverse由右向左，column由上向下。about:
display:flex;
flex-wrap{nowrap|wrap|wrap-reverse}
nowrap（默认）不换行，wrap换行（第一行在上方）Horizontal alignment:
justify-content{flex-start|flex-end|center|space-between|space-around}
item在水平方向的对齐方式。Vertical alignment:
align-items{flex-start|flex-end|center|baseline|stretch}
用于指定垂直方向的对齐方式。
equally distributed:
display: flex;
justify-content: space-between;Multi-line alignment:
algin-content{flex-start|flex-end|center|space-between|space-around|stretch}
该属性只作用于多行的情况下，用于多行的对齐方式。Flex layout of display attribute in CSS_display up and down layout_Cui Shixun's Blog-CSDN Blog
position
The word is on the picture, and the bottom of the child page is fixed
父级：
position属性为relative(相对定位)。
子级：
position属性为absolute（绝对定位），并设置它距离div的顶部为0px。css - Several ways to fix the bottom of the css page_css fixed at the bottom_C
https://blog.csdn.net/CHS007chs/article/details/81865355
float
Float left and right:
float:left;
float:right;