.box-login {
    -ms-flex-align: center;
    align-items: center;
    background: #f4d854;
    display: -ms-flexbox;
    display: flex;
    -ms-flex-direction: column;
    flex-direction: column;
    height: 100vh;
    -ms-flex-pack: center;
    justify-content: center;
    position:relative;
    overflow:hidden;
    width: 100%;
}
.box-login:before{position:absolute;width:1200px;height:1200px;top:calc(50% - 600px);left:50%;margin-left:-600px;content:"";background:transparent url(../images/trongdong.png) no-repeat center center;background-size:100% auto;opacity:.3}
.box-login:before{-webkit-animation-name:rotate;-webkit-animation-duration:60s;-webkit-animation-iteration-count:infinite;-webkit-animation-timing-function:linear;-moz-animation-name:rotate;-moz-animation-duration:60s;-moz-animation-iteration-count:infinite;-moz-animation-timing-function:linear}
@-webkit-keyframes rotate{
		from{-webkit-transform:rotate(0)}
		to{-webkit-transform:rotate(360deg)}
}
@-moz-keyframes rotate{
		from{-moz-transform:rotate(0)}
		to{-moz-transform:rotate(360deg)}
}