#seokotscrollbutton {
    position: fixed;
    cursor: pointer;
    display: none;
}
#seokotscrollbutton:before {
    content: "";
    width: 0;
    height: 0;
    border-left: 15px solid transparent;
    border-right: 15px solid transparent;
    border-bottom: 25px solid #fff;
    margin: auto;
    display: block;
    margin-top: calc(50% - 16px);
}