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.block {
width: 300px;
margin: 50px auto 0;
line-height: 2.5;
}
.block span {
position: relative;
display: block;
border-bottom: 1px dashed #000;
}
.block span:after {
content: '';
position: absolute;
left: 0;
bottom: 0;
right: 0;
height: 100%;
width: 100%;
background-color: #fff;
}
.block span:nth-child(1):after {
transition: height 0.6s ease 1.1s;
}
.block span:nth-child(2):after {
transition: height 0.6s ease 1.45s;
}
.block span:nth-child(3):after {
transition: height 0.6s ease 1.8s;
}
.block span:nth-child(4):after {
transition: height 0.6s ease 2.15s;
}
.block span:nth-child(5):after {
transition: height 0.6s ease 2.5s;
}
.block.active span:after {
height: 0;
}
window.onload = function() {
document.getElementById("block").classList.add("active")
};