css flexbox水平垂直

display: -webkit-box;
display: -webkit-flex;
display: -moz-box;
display: -moz-flex;
display: -ms-flexbox;
display: flex;

/* 水平居中*/
-webkit-box-align: center;
-moz-box-align: center;
-ms-flex-pack:center;/* IE 10 */

-webkit-justify-content: center;
-moz-justify-content: center;
justify-content: center;/* IE 11+,Firefox 22+,Chrome 29+,Opera 12.1*/

/* 垂直居中 */
-webkit-box-pack: center;
-moz-box-pack: center;
-ms-flex-align:center;/* IE 10 */

-webkit-align-items: center;
-moz-align-items: center;
align-items: center;