body {
    font-family: Arial, sans-serif;
    background: #f0f2f5; margin: 0; padding: 20px;
}
.container {
    max-width: 800px; margin: 0 auto;
    background: white;
    border-radius: 10px;
    padding: 20px;
    box-shadow: 0 0 10px rgba(0,0,0,0.1);
}
h3 {
    text-align: center;
}
#chat-box {
    height: 70vh;
    overflow-y: auto;
    border: 1px solid #ddd;
    padding: 10px;
    margin: 20px 0;
    background: #f9f9f9;
    border-radius: 8px;
}
.message {
    margin: 8px 0;
    padding: 8px;
    background: #e3f2fd;
    border-radius: 8px;
}
.message strong {
    color: #1976d2;
}
.time {
    float: right;
    font-size: 0.8em;
    color: #666;
}
form {
    display: flex;
    gap: 10px;
}
input[type="text"] {
    flex: 1;
    padding: 12px;
    border: 1px solid #ccc;
    border-radius: 8px;
}
button {
    padding: 12px 20px;
    background: #1976d2;
    color: white;
    border: none;
    border-radius: 8px;
    cursor: pointer;
}
button:hover {
    background: #1565c0;
}