hr {
    -moz-border-bottom-colors: none;
    -moz-border-left-colors: none;
    -moz-border-right-colors: none;
    -moz-border-top-colors: none;
    border-color: #000 ;
    border-image: none;
    border-style: solid none none;
    border-width: 1px 0 0;
    margin-bottom: 20px;
    margin-top: 20px;
}