CSS 垂直居中。

1,display: table; display: table-cell

<div >

<div > Testaaaaaaaaaaaaaaaaaaa<br/>

Testaaaaaaaaaaaaaaaaaaa<br/>

</div>

</div>

display:flex;

flex-direction: row | row-reverse | column | column-reverse;

flex-wrap: nowrap | wrap | wrap-reverse;

flex-flow: <‘flex-direction’> || <‘flex-wrap’>

justify-content: flex-start | flex-end | center | space-between | space-around;

align-items: flex-start | flex-end | center | baseline | stretch;

align-content: flex-start | flex-end | center | space-between | space-around | stretch;

order: <integer>;

flex-grow: <number>;

flex-shrink: <number>; /* default 1 */

flex-basis: <length> | auto;

flex: none | [ <'flex-grow'> <'flex-shrink'>? || <'flex-basis'> ]

align-self: auto | flex-start | flex-end | center | baseline | stretch;