* {
    box-sizing: border-box;
    margin: 0;
    padding: 0;
    font-family: Arial, sans-serif;
}

body {
    background-color: #f0f2f5;
}

.container {
    max-width: 800px;
    margin: 20px auto;
    padding: 20px;
    background: white;
    border-radius: 10px;
    box-shadow: 0 2px 10px rgba(0,0,0,0.1);
}

#chat-box {
    height: 500px;
    overflow-y: auto;
    padding: 20px;
    border: 1px solid #ddd;
    border-radius: 8px;
    margin-bottom: 20px;
    background: #f8f9fa;
}

.message {
    margin-bottom: 15px;
    padding: 10px 15px;
    border-radius: 20px;
    max-width: 70%;
    word-wrap: break-word;
}

.received {
    background: #e4e6eb;
    float: left;
    clear: both;
}

.sent {
    background: #0084ff;
    color: white;
    float: right;
    clear: both;
}

.input-area {
    display: flex;
    gap: 10px;
}

#message-input {
    flex: 1;
    padding: 12px;
    border: 1px solid #ddd;
    border-radius: 25px;
    outline: none;
    font-size: 16px;
}

#send-btn {
    padding: 12px 25px;
    background: #0084ff;
    border: none;
    border-radius: 25px;
    color: white;
    cursor: pointer;
    transition: background 0.3s;
}

#send-btn:hover {
    background: #0066cc;
}

.timestamp {
    font-size: 12px;
    color: #666;
    margin-top: 4px;
}