body {
    font-family: sans-serif;
    background-color: #f4f4f4;
    display: flex;
    justify-content: center;
    align-items: center;
    height: 100vh;
    margin: 0;
}

#app-container {
    background: white;
    border-radius: 8px;
    box-shadow: 0 2px 10px rgba(0,0,0,0.1);
    width: 500px;
    height: 600px;
    display: flex;
    flex-direction: column;
}

h1 {
    text-align: center;
    padding: 15px;
    border-bottom: 1px solid #ddd;
    margin: 0;
}

#chat-messages {
    flex-grow: 1;
    overflow-y: auto;
    padding: 20px;
    border-bottom: 1px solid #ddd;
}

.message {
    margin-bottom: 15px;
}

.message .username {
    font-weight: bold;
    color: #333;
}

.message .text {
    margin-left: 8px;
}

.message .timestamp {
    font-size: 0.75em;
    color: #999;
    margin-left: 10px;
}

#message-form {
    display: flex;
    padding: 15px;
}

#message-form input {
    border: 1px solid #ddd;
    padding: 10px;
    border-radius: 5px;
    flex-grow: 1;
}

#message-form #username-input {
    flex-grow: 0;
    width: 100px;
    margin-right: 10px;
}

#message-form button {
    border: none;
    background-color: #007bff;
    color: white;
    padding: 10px 15px;
    border-radius: 5px;
    cursor: pointer;
    margin-left: 10px;
}

#message-form button:hover {
    background-color: #0056b3;
}