1.css

/* HOVERMEMBERLIST PLUGIN by ᴘᴜʀᴘʟᴇ ᴡɪᴢᴀʀᴅ#0984 */

.membersWrap-2h-GB4, .membersWrap-2h-GB4 .scroller-2FKFPG {
    position: absolute;
    right: 0;
    top: 0;
    bottom: 0;
}

/* GROUP HEADER */
.membersGroup-v9BXpm {
    opacity: 0;
    transition: all 500ms;
}

.membersWrap-2h-GB4:hover .membersGroup-v9BXpm {
    transition: all 500ms;
    opacity: 1;
}

/* PRE-HOVER DIV to fix spam-open bugs */

.membersWrap-2h-GB4:before {
    width: 15px;
    content: "";
}

/* MOVE THE MEMBERLIST DIV TO THE RIGHT */

.membersWrap-2h-GB4 {
    -webkit-transform: translateX(220px);
    transform: translateX(220px);
    position: absolute;
}

/* MEMBERLIST CONTENT */

.members-1998pB {
    width: 265px;
    overflow: hidden;
    border-radius: .5em 0 0 .5em;
    transition: all 500ms;
    -webkit-transition: all 500ms;
}

.membersWrap-2h-GB4:hover .members-1998pB {
    -webkit-transform: translateX(-220px);
    transform: translateX(-220px);
    overflow: auto;
    width: 265px!important;
    transition: all 500ms;
    background-color: var(--darkgrey5)!important;
}

/* RESIZE CHAT CONTENT TO SHOW THE SCROLLBAR */

.chatContent-a9vAAp { margin-right: 60px;}