#conteticker { /* the outer div with the black border */
    width: 980px;
    height: 18px;
    margin: 0;
    padding: 0;
    overflow: hidden;
}

#mascara { /* that serves as a mask. so you get a sort of padding both left and right */
    position: relative;
    width: 100%;
    top: 0px;
    height: 18px;
    /*width: 718px;*/
    overflow: hidden;
}

#dataticker { /* that's your list */
    position: relative;
    /*left: 750px;*/
    font: 11px Verdana;
    list-style: none;
    margin: 0;
    padding: 0;
}

.itemticker {
    float: left; /* important: display inline gives incorrect results when you check for elem's width */
    margin: 0;
    padding-right: 50px;
    padding-left: 18px;
    background-image: url(../images/arrow.png);
    background-position: left;
    margin-top: 5px;
    background-repeat: no-repeat;
    /*background: #fff;*/
}