.contents_box li.link_window_icon:after {
    content: "";
    display: block;
    position: absolute;
    right: 3px;
    top: 41%;
    width: 14px;
    height: 14px;
    background-image: url(/content/dam/au-com/support/service/mobile/procedure/images/st_icon_link_09.png);
    background-repeat: no-repeat;
    background-size: 100%;
    border-top: 0;
    border-right: 0;
    transform: rotate(0deg);
}

@media screen and (max-width: 767px) {
    .contents_box li.link_window_icon:after {
        width: 11px;
        height: 11px;
    }
}