.zextra-toc {
    position: sticky;
    top: 20px;
    max-width: 250px;
    border: 1px solid #ddd;
    padding: 10px;
    background: #f9f9f9;
}

.zextra-toc ul {
    list-style: none;
    padding-left: 0;
}

.zextra-toc li {
    margin-bottom: 5px;
}

.zextra-toc a {
    text-decoration: none;
    color: #007bff;
}

.zextra-toc a:hover {
    text-decoration: underline;
}

/* .zextra-toc a:active, */
.zextra-toc a[data-active="true"] {
    color : green;
}