.rst-content div.math {
    position: relative;
}

.rst-content div.math .eqno {
    position: absolute;
    right: 0;
    top: 0;
    bottom: 0;
    display: flex;
    flex-direction: row;
    align-items: center;
    z-index: 100;
}

.rst-content div.math .eqno:hover .headerlink {
    opacity: 1;
}