※デベロッパーツール等でソースコードをご確認ください(Please check using Developer tools)
.wrap {
width: 768px;
margin: 50px auto 0;
}
.block {
opacity: 0;
width: 100%;
padding: 66.625% 0 0;
transform: scale(1.05);
transition: opacity .8s ease-out, transform 1.8s ease-out;
background: url(/img/a.jpg) no-repeat center top;
background-size: cover;
}
.block.active {
opacity: 1;
transform: scale(1);
}
@media screen and (max-width:640px){
.wrap {
width: 100%;
}
}
$(window).on('load', function(){
$(".block").addClass("active");
});