#chat-container {
    width: 100%;
    max-width: 600px;
    height: 400px;
    border: 1px solid #ccc;
    padding: 10px;
    overflow-y: scroll;
    margin: 0 auto;
}

#messages {
    list-style-type: none;
    padding: 0;
    margin: 0;
}

#messages li {
    padding: 5px 10px;
    margin-bottom: 5px;
    background: #f1f1f1;
    border-radius: 5px;
}