@media screen and (min-width: 560px) {
  .news-detail-nav-prev a::before{
    left: 24px;
    background: url(/cms/livepower_hp/images/common/arw_white.png) center no-repeat;
  }
}

@media screen and (max-width: 559px) {
    .news-detail-nav-prev a::before {
        left: 24px;
        background-image: url(/cms/livepower_hp/images/common/arw_white.png);
    }
}