ol.clean {
    list-style: none;
    counter-reset: item;
}

ol.clean li {
    counter-increment: item;
    margin-bottom: 5px;
}

ol.clean li:before {
    margin-right: 10px;
    content: counter(item);
    font-weight: bold;
    width: 29px;
    text-align: center;
    display: inline-block;
}