.arrow-up {
    background: url(../../images/arrow_up.png) no-repeat;
    display:block;
    height: 20px;
    width: 20px;
    float: left;
}

.arrow-down {
    background: url(../../images/arrow_down.png) no-repeat;
    display:block;
    height: 20px;
    width: 20px;
    float: left;
}