html, body {
    margin: 0; padding: 0;
}
html {
    box-sizing: border-box;
}
body {
    font-size: 12px;
    font-family: "Microsoft YaHei";
}
*,
*:before,
*:after {
    box-sizing: inherit;
}
.flex-box {
    display: flex;
    display: -webkit-box;
    display: -moz-box;
    display: -ms-flexbox;
    display: -webkit-flex;
}
.ai-center {
    align-items:center;
    -webkit-align-items:center;
    box-align:center;
    -moz-box-align:center;
    -webkit-box-align:center;
}
.jc-center {
    -webkit-justify-content: center;
    justify-content: center;
    -moz-box-pack: center;
    -webkit-moz-box-pack: center;
    box-pack: center;
}