ul li ul {
    margin-left: 20px;
}

ul {
    position: relative;
    list-style: none;
}

.sitemap_list ul:before {
    content: "";
    position: absolute;
    left: -20px;
    top: 0;
    background: #e4e4e4;
    width: 2px;
    height: 100%;
}

.sitemap_block div {
    margin: 50px;
}