darkfi/doc/theme/tabs.css

.mdbook-tabs {
    display: flex;
}

.mdbook-tab {
    background-color: var(--table-alternate-bg);
    padding: 0.5rem 1rem;
    cursor: pointer;
    border: none;
    font-size: 1.6rem;
    line-height: 1.45em;
}

.mdbook-tab.active {
    background-color: var(--table-header-bg);
    font-weight: bold;
}

.mdbook-tab-content {
    padding: 1rem 0rem;
}

.mdbook-tab-content table {
    margin: unset;
}