.cur{
    position: absolute;
    top: 0;
    left: 0;
    z-index: 6;
    width: 3px;
    height: 30px;
    visibility: hidden;
    transition: all .15s ease-in-out;
}
.cur.show{
    visibility: visible;
}
.cur::after{
    content: "";
    position: absolute;
    left: 0;
    top: 4px;
    width: 3px;
    height: 22px;
    background: #df2d2d;
}