/*---------------mask---------------*/
.mask{
    width: 100%;
    height: 100%;
    position: fixed;
    top: -100%;
    left: 0;
    z-index: 1000000;
    -webkit-animation: mydown 3s ease-in 1;
    animation: mydown 3s ease-in 1;
    -webkit-animation-fill-mode:both;
            animation-fill-mode:both
}
.mask img{
        width: 100%;
        max-width: 100%;
    }

.mask div{
  position: absolute;
  top: 0;
  right: 0;
  width: 50px;
  height: 50px;
  font-size: 24px;
  color: #666;
  cursor: pointer;
}
.mask div:hover{
  color: red;
}
@-webkit-keyframes mydown {
  0% {top:-100%;}
  100% {top:0px;}
}
@-webkit-keyframes mydown {
  0% {top:-100%;}
  100% {top:0px;}
}
@keyframes mydown {
  0% {top:-100%;}
  100% {top:0px;}
}