sphinx-dropdown.css

.octicon {
    display: inline-block;
    vertical-align: text-top;
    fill: currentColor;
}
details.dropdown .summary-title {
    -webkit-user-select: none;
       -moz-user-select: none;
        -ms-user-select: none;
            user-select: none;
    /* don't overlap the chevron */
    padding-right: 3em!important;
  }
details.dropdown:hover {
    cursor: pointer;
}
details.dropdown .summary-content {
    cursor: default;
}
details.dropdown summary {
    padding: 1em;
    /* hide the default triangle marker */
    list-style: none;
}
/* chrome doesn't yet support list-style */
details.dropdown summary::-webkit-details-marker {
    display: none;
}
details.dropdown summary:focus {
    outline: none;
}
details.dropdown summary:hover .summary-up svg,
details.dropdown summary:hover .summary-down svg {
    opacity: 1;
}
details.dropdown .summary-up svg,
details.dropdown .summary-down svg {
    opacity: 0.6;
}
details.dropdown .summary-up,
details.dropdown .summary-down {
    pointer-events: none;
    position: absolute;
    top: 0.75em;
    right: 1em;
}
details.dropdown .summary-up svg,
details.dropdown .summary-down svg {
    display: block;
}
details.dropdown[open] .summary-down{
    visibility: hidden;
    /* z-index: -1; */
}
details.dropdown:not([open]) .summary-up{
    visibility: hidden;
    /* z-index: -1; */
}

/* Ellipsis added when no title */
details.dropdown summary .octicon.no-title {
    vertical-align: middle;
}
details.dropdown[open] summary .octicon.no-title{
    visibility: hidden;
}

/* Transition animation */
details.dropdown.fade-in[open] summary ~ * {
    animation: fade-in .5s ease-in-out;
    -moz-animation: fade-in .5s ease-in-out ;
    -webkit-animation: fade-in .5s ease-in-out
}
details.dropdown.fade-in-slide-down[open] summary ~ * {
    animation: fade-in .5s ease-in-out, slide-down .5s ease-in-out;
    -moz-animation: fade-in .5s ease-in-out, slide-down .5s ease-in-out ;
    -webkit-animation: fade-in .5s ease-in-out, slide-down .5s ease-in-out
}
@keyframes fade-in {
    0%    {
        opacity: 0;
    }
    100%  {
        opacity: 1;
    }
}
@keyframes slide-down {
    0%    {
        transform: translate(0px, -10px)
    }
    100%  {
        transform: translate(0px, 0px)
    }
}