asdd

by talla13

HTML

<span class='btn'>Кнопка</span>

CSS

.btn{
    position:relative;
    cursor:pointer;
}
.btn:before, .btn:after{
    content:' ';
    display:block;
    position:absolute;
    left:50%;
    right:50%;
    border-bottom:1px solid #44d;
    transition:all .3s;
}
.btn:after{
    bottom:0;
}
.btn:before{
    top:0;
}
.btn:hover:after, .btn:hover:before{
    left:0;
    right:0;
}