cms-system/docs/gitbook/gitbook-plugin-anchors/plugin.css

a.plugin-anchor {
    color: inherit !important;
    display: none;
    margin-left: -30px;
    padding-left: 40px;
    cursor: pointer;
    position: absolute;
    top: 0;
    left: 0;
    bottom: 0;
}

a.plugin-anchor i {
    margin-left: -30px;
    font-size: 15px !important;
}

h1, h2, h3, h4, h5, h6 {
    position: relative;
}

h1:hover a.plugin-anchor, h2:hover a.plugin-anchor, h3:hover a.plugin-anchor,
h4:hover a.plugin-anchor, h5:hover a.plugin-anchor, h6:hover a.plugin-anchor {
    display: inline-block;
}

.book .book-body .page-wrapper .page-inner section.normal {
    overflow: visible;
}