#sidebar{height:100vh;overflow-y:auto}.chat-window{height:70vh;overflow-y:auto;padding:10px;background-color:#f8f9fa;border:1px solid #ddd}.chat-input{position:sticky;bottom:0;background-color:#fff;padding:10px}.message{margin-bottom:10px}.message .sender{font-weight:bold}.message .text{margin:0}.flex{display:flex;justify-content:center;align-items:center;text-align:center}