.loadonDemand-chatui {
    height: 500px;
    width: 40%;
    margin: 0 auto;
    display: flex;
    flex-direction: row;
    gap: 50px;
}

.loadonDemand-chatui .chat_user2_avatar {
    background-image: url('https://ej2.syncfusion.com/react/demos/src/chat-ui/images/andrew.png');
    background-color: unset;
}   

@media only screen and (max-width: 850px) {
    .loadonDemand-chatui {
        flex-direction: column;
        height: 500px;
        width: 80%;
    }
    .chat-ui.control-section {
        height: 1050px;
    }
}