居中

position: absolute;
width: 90%;
min-height: 300px;
background: #fff;
left: 50%;
top: 50%;
-webkit-transform: translate3d(-50%, -50%, 0);
transform: translate3d(-50%, -50%, 0);
/*margin-top: -150px;*/
padding: 20px;
border-radius: 8px;