odoo18/addons/website_jitsi/static/src/css/chat_room.css

.o_wjitsi_room_modal .modal-dialog {
    top: 10%;
    max-width: 100vw;
    max-height: 100vh;
    width: 80%;
    margin: auto;
}

.o_wjitsi_room_modal .modal-body {
    height: 70vh;
    overflow: hidden;
    margin: 0;
}

.o_wjitsi_chat_room_loading {
    top: 40%;
}