body {
    margin: 0;
    font-family: Arial, sans-serif;
    background: #f7f7f7;
}

.container {
    display: flex;
    height: 100vh;
}

.sidebar {
    width: 300px;
    background: #222;
    color: white;
    padding: 15px;
    overflow-y: auto;
}

.sidebar h2 {
    margin-top: 0;
}

.contact {
    padding: 12px;
    background: #333;
    margin-bottom: 10px;
    border-radius: 5px;
    cursor: pointer;
}

.contact:hover {
    background: #444;
}

.chat {
    flex: 1;
    display: flex;
    flex-direction: column;
}

#contactName {
    background: #eee;
    padding: 15px;
    margin: 0;
}

.messages {
    flex: 1;
    padding: 15px;
    overflow-y: auto;
    background: white;
}

.message {
    padding: 8px 12px;
    margin-bottom: 10px;
    border-radius: 5px;
    max-width: 70%;
}

.message.sent {
    background: #d1ffd1;
    margin-left: auto;
}

.message.received {
    background: #f1f1f1;
}

.inputBox {
    display: flex;
    padding: 10px;
    background: #ddd;
}

#messageInput {
    flex: 1;
    padding: 10px;
}

#sendBtn {
    padding: 10px 20px;
    margin-left: 10px;
    cursor: pointer;
}