jellyfin-web/dashboard-ui/bower_components/emby-webcomponents/emby-collapse/emby-collapse.css

.emby-collapse {
    margin: .5em 0;
}

.collapseContent {
    border-width: 0;
    padding: 1.25em 1.25em;
    height: 0;
    transition-property: height;
    transition-duration: 300ms;
    overflow: hidden;
    background: #222;
}

.emby-collapsible-button {
    margin: 0;
    display: flex;
    align-items: center;
    text-transform: none;
    width: 100%;
    text-align: left;
    border: 0;
    text-transform: none;
    border-bottom: 1px solid #333;
    padding-left: .1em;
    background: transparent;
    box-shadow: none;
}

.emby-collapse-expandIcon {
    transform-origin: 50% 50%;
    transition: transform 180ms ease-out;
    position: absolute;
    right: .5em;
    font-size: 1.5em;
}

.emby-collapse-expandIconExpanded {
    transform: rotate(180deg);
}

.emby-collapsible-title {
    margin: 0;
    padding: 0;
}