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.block {
position: relative;
display: block;
width: 768px;
margin: 50px auto 0;
}
.block img {
width: 100%;
}
.block:after {
content: "";
position: absolute;
right: 0;
bottom: 0;
z-index: 1;
display: block;
width: 100%;
height: 100%;
background: #55310e;
transition: height 1.0s cubic-bezier(1, 0, 0, 1);
}
.active.block:after {
height: 0;
}
@media screen and (max-width:640px){
.block {
width: 100%;
}
}
$(window).on('load', function(){
$(".block").addClass("active");
});