qmk-firmware/docs/qmk_custom_dark.css

.sidebar li.active {
    background-color: #555;
}

.markdown-section p.tip,
.markdown-section tr:nth-child(2n) {
 background-color:#444;
}

.markdown-section tr {
    border-top: 1px solid #555;
}

.markdown-section td, .markdown-section th {
    border: 1px solid #555;
}

.markdown-section p.tip code {
    background-color: #555;
    color: #fff;
}

.page_toc code {
    background-color: #555;
}

.markdown-section hr, .search {
    border-bottom: 1px solid #777 !important;
}